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Study Name:
Orange River Integrated Water Resources Management Plan
Report Title:
Summary of Water Requirements from the Orange River
Submitted By: WRP Consulting Engineers, Jeffares and Green, Sechaba Consulting, WCE Pty Ltd,
Water Surveys Botswana (Pty) Ltd
Authors:
HG Mare
Date of Issue: August 2007
Distribution:
Botswana: DWA: 2 copies (Katai, Setloboko)
Lesotho: Commissioner of Water: 2 copies (Ramosoeu, Nthathakane)
Namibia: MAWRD: 2 copies (Amakali)
South Africa: DWAF: 2 copies (Pyke, van Niekerk)
GTZ: 2 copies (Vogel, Mpho)
Reports:
Review of Existing Infrastructure in the Orange River Catchment
Review of Surface Hydrology in the Orange River Catchment
Flood Management Evaluation of the Orange River
Review of Groundwater Resources in the Orange River Catchment
Environmental Considerations Pertaining to the Orange River
Summary of Water Requirements from the Orange River
Water Quality in the Orange River
Demographic and Economic Activity in the four Orange Basin States
Current Analytical Methods and Technical Capacity of the four Orange Basin
States
Institutional Structures in the four Orange Basin States
Legislation and Legal Issues Surrounding the Orange River Catchment
Summary Report

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TABLE OF CONTENTS
1
INTRODUCTION ..................................................................................................................... 1
1.1 General ......................................................................................................................... 1
1.2 Objective of the study ................................................................................................... 7
1.3 Purpose and Structure of this Report........................................................................... 9
2
DATA BASE INVENTORY .................................................................................................... 10
2.1 General ....................................................................................................................... 10
2.2 Description of the database inventory........................................................................ 10
3
WATER REQUIREMENTS AND RETURN FLOWS ............................................................ 15
3.1 General ....................................................................................................................... 15
3.2 Vaal River System (RSA) ........................................................................................... 16
3.3 Orange River System ................................................................................................. 25
3.4 Namibia Water Requirements .................................................................................... 36
3.5 Botswana Water Requirements.................................................................................. 39
3.6 Lesotho Water Requirements..................................................................................... 42
3.7 Assurance of Supply................................................................................................... 47
3.8 Efficiency of Water Use .............................................................................................. 50
4
CONCLUSIONS AND RECOMMENDATIONS .................................................................... 55
4.1 Conclusions ................................................................................................................ 55
4.2 Recommendations...................................................................................................... 57
5
REFERENCES ...................................................................................................................... 59
LIST OF FIGURES AND TABLES
Table 1-1: Orange River Water Balance at 2005 Development Level.................................. 4
Figure 1-3: Major Water Demands along the Lower Orange River. ..................................... 4
Figure 1-4: Major Water Transfer Schemes from Gariep and Vanderkloof dams. ............... 6
Figure 1-5: Phase 1 of the Lesotho Highlands Water Project............................................... 7
Table 2-1 : Main sub-catchments in the Vaal River catchment .......................................... 10

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Table 2-2: Main sub-catchments in the Orange River catchment....................................... 11
Table 2-3 : Sub-catchments within each main sub-catchment ........................................... 12
Table 2-4: Data elements included in the inventory ............................................................ 14
Figure 3-1: Simplified schematic of the Integrated Vaal River and Orange River system . 16
Table 3-1: Demands imposed on the main Vaal River System .......................................... 17
Table 3-2: Examples of monthly demand distributions for demands within the Vaal River
catchment for 1994 development ........................................................................................ 20
Table 3-3: Demands imposed on the smaller systems within the Vaal River Basin .......... 21
Table 3-4: Summary of Urban/Industrial and Mining related return flows .......................... 24
Table 3-5: Return flows from main irrigation schemes........................................................ 24
Table 3-6: Demands imposed on the main Orange River System (Orange River Project) 26
Table 3-7:Monthly Demands distribution for demands within the greater Orange River
System at 2005 Development Levels (million cub. m/a) ..................................................... 29
Table 3-8: Demands imposed on the other sub-systems within the Orange River Basin.. 33
Table 3-9: Return flow estimations from main irrigation areas ........................................... 35
Table 3-10 : Surface area of the Orange River Basin in Namibia....................................... 36
Table 3-11: Estimated Population in the Orange River Basin in Namibia .......................... 37
Table 3-12 : Estimated water requirements in the Orange River Basin within Namibia..... 39
Table 3-13: Catchment data of the Orange River Basin ..................................................... 40
Table 3-14 : Population data................................................................................................ 41
Table 3-15: Estimated water requirement for Botswana..................................................... 42
Table 3-16 : Distribution of Lesotho's Population by District............................................... 42
Figure 3-2 : Population With and Without AIDS for Lesotho (1986 - 2015)....................... 43
Table 3-17 : Summary of urban/Industrial/rural demand projections for Lesotho .............. 45
Table 3-18 : Maximum Areas Suitable for Irrigation (with a 15% failure chance)............... 46
Table 3-19 : Ecological water requirements supplied from LHWP ..................................... 46

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Table 3-20 :User Categories and Priority Classifications used for the Vaal System.......... 48
Table 3-21: User Categories and Priority Classifications used for the Main Orange System
.............................................................................................................................................. 49
Table 3-22: User Categories and Priority Classifications used for the Caldon/Modder ........
Sub-system .......................................................................................................................... 50
Table 3-23 : Summary of conveyance losses and possible savings .................................. 51
Table 3-24 : Percentage of Irrigation systems in the selected five schemes ..................... 51
Table 3-25: Possible savings through WC/WDM in the irrigation sector ............................ 52
Table 3-26 : Estimated Canal Losses in the Orange and Modder/Riet systems................ 52
Table 3-27 : Losses within the Rand Water supply area .................................................... 54

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1
INTRODUCTION
1.1
General
The Orange River originates in the Lesotho Highlands and flows in a westerly direction
2 200 km to the west coast where the river discharges into the Atlantic Ocean (see Figure
1-1). The Orange River basin is one of the largest river basins south of the Zambezi with a
catchment area of approximately 0.9 million km2.
Figure 1-1: Orange River
It has been estimated that the natural runoff of the Orange River basin is in the order of
11 600 million m3/a of which approximately 4 000 million m3/a originates in the Lesotho
Highlands and approximately 900 million m3/a from the contributing catchment
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downstream of the Orange/Vaal confluence which includes part of Namibia and a small
portion in Botswana feeding the Nossob and Molopo rivers. Whether or not these two
rivers directly contribute to the Orange River is an outstanding issue which will be
addressed during the study. The remaining 6 700 million m3/a originates from the areas
contributing to the Vaal, Caledon, Kraai and Middle Orange rivers.
It should be noted that much of the runoff originating from the Orange River downstream of
the Orange Vaal confluence is highly erratic (coefficient of variability greater than 2) and
cannot be relied upon to support the various downstream demands unless further storage
is provided.
Figure 1-2: Approximate Water Balance for Natural Runoff in the Orange River Basin
The water flowing into the Orange River from the Fish River in Namibia (near the river
mouth) could theoretically be used to support some of the downstream demands,
particularly the environmental demands at the river mouth.
To date, however, the
contributions from the Fish River (in Namibia) cannot be utilised to support any
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downstream demands since these demands are currently supplied with water from
Vanderkloof Dam which must be released well in advance since the water takes 2 to 6
weeks to reach the mouth (some 1 400 km away). Any water flowing into the Orange
River from the Namibian Fish River will therefore add to the water already released from
Vanderkloof Dam since it is currently not possible to stop or store the additional water
once it has been released.
The figures indicated in Figure 1.2 refer to the natural runoff which would have occurred
had there been no developments in the catchment. The actual runoff reaching the river
mouth (estimated to be in the order of 5 500 million m3/annum) is considerably less than
the natural value (over 11 000 million m3/annum). The difference is due mainly to the
extensive water utilisation in the Vaal River basin, most of which is for domestic and
industrial purposes. Large volumes of water are also used to support the extensive
irrigation (estimated to be in the order of 1 800 million m3/annum) and some mining
demands (approximately 40 million m3/annum) occurring along the Orange River
downstream of the Orange/Vaal confluence as well as some irrigation in the Lower Vaal
catchment and Eastern Cape area supplied through the Orange/Fish Canal. In addition to
the water demands mentioned above, evaporation losses from the Orange River and the
associated riparian vegetation account for between 500 million m3/a and 1 000 million m3/a
depending upon the flow of water (and consequently the surface area) in the river
(Mckenzie et al, 1993, 1994 and 1995). An approximate water balance for the Orange
River is given in Table 1-1 to provide perspective on the various demands supported from
the river.
Several new developments have already been commissioned or have been identified as
possible future demand centres for water along the Lower Orange River. In Namibia such
developments include the Haib copper mine, Skorpion lead and zinc mine (already
developed), the Kudu gas fired power station at Oranjemund and several irrigation projects
for communal and commercial irrigation along the northern riverbank. Similar potential
also exists on the South African side of the river with particular need to develop irrigation
for previously disadvantaged farmers. In Lesotho there is considerable development
planned for the Lesotho Lowlands area and also the potential for further transfers from the
Lesotho Highlands Water Project. In Botswana, the developments that may influence the
Orange River are restricted mainly to groundwater abstraction.
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Table 1-1: Orange River Water Balance at 2005 Development Level
Water Balance Component
Volume (million m³/a)
Environmental Requirement
900 (1)
Namibia
120 (2)
Lesotho & Transfers to RSA
820 (3)
RSA Orange River Demand
2 560 (4)
RSA Vaal River Demand
1 560 (5)
Evaporation & losses
1 750 (6)
Spillage
3 780 (7)
Total
11 490
Spillage under natural conditions
10 900
Notes
(1) - Includes natural evaporation losses from Orange River.
(2) - Includes water use from Orange & Fish rivers.
(3) ­ With Full Phase 1 of LHWP active.
(4) ­ Includes transfers to the Eastern Cape.
(5) ­ Vaal Demand supplied from locally generated runoff.
(6) ­ Excludes evaporation losses from the as it is already included in component 1.
(7) ­ Average spillage at 2005 development level
Figure 1-3: Major Water Demands along the Lower Orange River.
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In Lesotho, the first phase of the Lesotho Highlands Water Project was recently completed
and represents one of the largest water transfer schemes in the world. Some details of the
scheme are shown in Figure 1.5. It should be noted that the water transfers shown in the
figure are approximate values only and are likely to change due to revision of
environmental requirements etc.
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Figure 1-4: Major Water Transfer Schemes from Gariep and Vanderkloof dams.
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Figure 1-5: Phase 1 of the Lesotho Highlands Water Project.
1.2
Objective of the study
In view of the existing and possible future developments which will influence the availability
of water in the Orange River, a project has been initiated by ORASECOM and
commissioned and funded by GTZ involving all four basin states (Botswana, Lesotho,
Namibia and South Africa. The main objective of the project is to facilitate the development
of an Integrated Water Resources Management Plan for the Orange River Basin. The plan
will in turn facilitate the following specific objectives:
· Maximise benefits to be gained from Orange River water;
· Harmonise developments and operating rules;
· Foster peace in the region and prevention of conflict;
· Encourage proper and effective disaster management;
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· Ensure that developments are sustainable and encourage the maintenance of
bio-diversity in the basin, and
· Management of potential negative impacts of current and possible future
developments.
In order to achieve the above objective it is envisaged that the resulting Water Resources
Development Plan will be founded on the following four basic principles:
· Reasonable utilisation of available water resources;
· Equitable accrual of benefits to basin states;
· Sustainable utilisation of water resources, and
· Minimisation of harm to the environment.
The strategy to be adopted by the project team to meet the objectives should involve the
following:
· Sharing of information on existing and proposed future developments;
· Facilitation of a common understanding of key issues based on comparable
technical and institutional capacity;
· Development of comparable legislation and institutional structures;
· Adoption of comparable standards and management approaches;
· The development of a Water Resource Management Plan for the future
development and management of the water resources of the Orange River.
It is anticipated that the development of the Water Resource Management Plan will be
undertaken in phases and the remainder of this document refers to the work involved with
Phase 1 of the project. Phase 1 will involve the following:
· A desktop study to establish the status quo within the basin and to create an
agreed base from which the subsequent phases of the project can be developed;
· To facilitate capacity building where possible in order to strengthen expertise
throughout the four basin states;
· To identify and highlight deficiencies in the knowledge base which must be
addressed before the Water Resource Management Plan can be finalised. Some
fieldwork may be required in subsequent phases of the project;
· To develop a preliminary Water Resource Management Plan which can be used
as the basis from which the final plan can ultimately be developed;
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· To develop a draft scope of work for subsequent phases of the project from which
a Terms of Reference can be developed by the Client.
· An inaugural meeting to discuss the project and in particular the expected content
for the Inception Report was held in Botswana on 8 February 2004.
1.3
Purpose and Structure of this Report
This report is used to summarise the findings from the Water Requirements Task. A
description of the data base inventory will be given in Section 2 of the report. Section 3
will include a summary of the demands and return flows captured in the excel data base
prepared for the current and future demands. Conclusions and recommendations are
given in Section 4.
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2
DATA BASE INVENTORY
2.1
General
This component of the Water Requirements task involved the compiling of the latest
available water demand and return flow data from reports of relevant studies. An initial
database was developed in Excel which will later in the study be incorporated in the
Access database which is developed as part of Task 2 of this study. The preliminary Excel
data base was populated with water demand data per main water use sector for each of
the selected geographic areas, as obtained from existing reports. Details of the database
inventory will be given in the sections to follow.
2.2
Description of the database inventory
For the purpose of the database inventory, the study area was divided into different sub-
catchments mainly according to those defined in the available study reports. These sub-
catchments were sorted first according to the two major river catchments, the Vaal River
and Orange River catchment, and then according to the main sub-catchments within each
major river catchment. The Vaal River catchment is divided into five main sub-catchments
as described in Table 2.1 and shown in Figure A-1 of Appendix A.
Table 2-1 : Main sub-catchments in the Vaal River catchment
Main Sub-catchment
Description
Name
Area (km²)
Upper Vaal
38 638
Vaal River catchment from Vaal Dam and upstream
Vaal Barrage
8 651
Vaal River catchment between Vaal Dam & Vaal Barrage
Middle Vaal
60 836
Vaal River catchment between Vaal Barrage and Bloemhof Dam
Lower Vaal
53 787
Vaal River catchment downstream of Bloemhof Dam excluding the the Riet
and Modder River catchments
Riet/Modder
27 627
The combined Riet and Modder River catchments
Total
189 539
Total Vaal River Catchment
The Orange River catchment (excluding the Vaal River catchment) is divided into seven
main sub-catchments which also take into account the country wherein it is located. The
Orange River main sub-catchments is described in Table 2.2 and shown in Figure A-1 of
Appendix A.
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The sub-catchments as per main sub-catchment are given in Table 2.3 for both the Vaal
and Orange River catchments and are shown in Figure A-1 of Appendix A. Several data
elements were covered in the inventory with regards to the following data categories: i.e.
catchment area, water resource, water requirements for urban/industrial, mines, power
stations, strategic industries, irrigation, rural domestic, livestock, ecological requirements,
losses and groundwater use. For each of the sub-catchments as defined in Table 2.3
metadata were provided for all the selected data elements as and when it was available
from existing documents.
Table 2-2: Main sub-catchments in the Orange River catchment
Main Sub-catchment
Description
Name
Area (km²)
Senqu
24 752
Upper reaches and origin of the Orange River in Lesotho
Upper Orange
48 595
Orange River upstream of Vanderkloof Dam and downstream of
Welbedacht Dam and the Lesotho Border at Oranjedraai.
Caledon
15 245
Caledon River catchment from Welbedacht Dam and upstream
(includes parts of RSA and Lesotho)
Lower Orange RSA
326 173
Orange River catchment downstream of Vanderkloof Dam and the Vaal
River confluence excluding the Lower Orange Areas located in
Botswana and Namibia
Lower Orange
71 000
The Orange River catchment located in Botswana
Botswana
Lower Orange
164 166
The Orange River catchment located in Namibia excluding the Fish
Namibia
River (Namibia)
Fish River Namibia
95 680
The total Fish River catchment in Namibia
Total
745 611
Total Orange River Catchment excluding Vaal River
Details of the data elements included in the inventory for each of the data categories are
given in Table 2.4. The gross and net areas are given for the sub-catchments. The gross
area refers to the total area in km² of the sub-catchment and the net area to the area that
contributes to the river runoff. Information with regards to the net area was unfortuanatelly
not always available from existing reports. In some areas which are relatively flat, part of
the sub-catchment drains to local pans, so that only a portion of the runoff will be reaching
the river. Only the area that contributes to runoff draining to the river is regarded as the
effective area and is referred to as the net catchment area. There will most probably also
be non contributing or endoreic areas in Namibia and Botswana, although no data was
available in this regard.
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The water resource data element refers to the surface water resource that is utilised to
supply the indicated demands. The water requirements for the main water use sectors
were given for the 2005, 2015 and 2025 development levels. Seven water uses sectors
were defined and include urban/industrial, mines, power stations, strategic industries,
irrigation, rural domestic and rural livestock. In addition to the seven water use sectors, the
ecological requirements and the main losses from water supply systems were added.
Groundwater use data is very seldom found in the existing reports. Detail of the actual
water use sectors utilising the groundwater was not always given, however it was clear
that the bulk of the groundwater was used to supply rural, smaller towns and some
irrigation requirements.
Table 2-3 : Sub-catchments within each main sub-catchment
Vaal River Basin
Orange River Basin (excluding Vaal)
Main sub-
Sub-catchment name &
Main sub-
Sub-catchment name &
catchment
reference no.
catchment
reference no.
Upper Vaal
R1-Delangesdrift
Senqu
L1-Katse Dam
R2-Frankfort
L2-Malatsi possible Dam
R3-Grootdraai Dam
L3-Mashai possible Dam
R4-Sterkfontein Dam
L4-Matsoku Weir
R5-Vaal Dam
L5-Mohale Dam
Vaal Barrage
R6-Vaal Barrage
L6-Ntoahe possible dam
R7-Klip River
L7-Tsoelike possible dam
R8-Suikerbosrand River
L8-Oranjedraai
R9-Allemanskraal Dam
*L9-Makhaleng 1
R10-Bloemhof Dam
*L10-Makhaleng 2
R11-Boskop Dam
Upper Orange
R36-Aliwal Noord
R12-Erfenis Dam
R37-Gariep Dummy Dam
Middle Vaal
R13-Klerkskraal Dam
R38-Vanderkloof Dam
R14-Possible Klipbank Dam
R39-Kraai River
R15-Klipdrift Dam
R40-Gariep Dam
R16-Koppies Dam
Caledon
L11-Hlotse possible dam
R17-Possible Kromdraai Dam
L12-Katjiesberg possible dam
R18-Johan Neser Dam
R41-Knellpoort Dam
R19-Possible Rietfontein Dam
R42-Waterpoort possible dam
R20-Rietspruit Dam
R43-Welbedacht Dam
R21-Lower Sand/Vet River
+L13-Hlotse possible dam 1
Lower Vaal
R22-Wentzel Dam
+L14-Hlotse possible dam 2
R23-Baberspan
$L15-Ngoajane possible dam 1
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Vaal River Basin
Orange River Basin (excluding Vaal)
Main sub-
Sub-catchment name &
Main sub-
Sub-catchment name &
catchment
reference no.
catchment
reference no.
R24-Taung Dam
$L16- Ngoajane possible dam 2
$L17- Muela Dam
R25-Spitskop Dam
Lower Orange
R44-Boegoeberg Weir
RSA
R26-Lower Harts
R45-Vioolsdrift/Mouth
R27-Vaalharts Weir
Lower Orange
B1- Nossop & Molopo catchment
Botswana
R28-De Hoop Weir
R29-Douglas Weir
Lower Orange
N1-Daan Viljoen Dam
Namibia
Riet/Modder
Aucampshoop
N2-Otjivero Dam
Kalkfontein Dam
N3-Nossop remainder
Krugersdrift Dam
N4-Nauaspoort Dam
Rustfontein Dam
N5-Oanob Dam
Tierpoort Dam
N6-Auob remainder
Tweerivier
N7-Tsamab Dam
N8-Dreihoek Dam
N9-Quaternary 442 & 481 &
remainder of 482 & 483
N10-Quaternary484
N11-Quaternary485
Fish River
N12-Hardap Dam
Namibia
N13-Konkiep
N14-Lower Fish possible dam
N15-Naute Dam
N16Seeheim
Notes : * - As part of the Lesotho Lowlands Study the Oranjedraai sub-catchment were sub-divided into these
two sub-catchments.
+ - As part of the Lesotho Lowlands Study the Hlotse sub-catchment were sub-
divided into these two sub-
catchments.
$ - As part of the Lesotho Lowlands Study the Katjiesberg sub-catchment were sub-divided into these three
sub-catchments.
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Table 2-4: Data elements included in the inventory
Data Category
Data elements
Catchments area
Gross area in km²
Net area in km²
Water Resource
Resource used to supply
the particular demand
Water Requirements
Urban/Industrial
Demand in million m3/a for 2005,
2015 & 2025 development level
Mines
Demand in million m3/a for 2005,
2015 & 2025 development level
Power Stations
Demand in million m3/a for 2005,
2015 & 2025 development level
Strategic Industries
Demand in million m3/a for 2005,
2015 & 2025 development level
Irrigation
Demand in million m3/a for 2005,
2015 & 2025 development level
Rural Domestic
Demand in million m3/a for 2005,
2015 & 2025 development level
Rural Livestock
Demand in million m3/a for 2005,
2015 & 2025 development level
Ecological Requirement
Requirement in million m3/a
Losses
Current loss in million m3/a level
Groundwater use
Groundwater use
Water use in million m3/a for 1995
development level
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3
WATER REQUIREMENTS AND RETURN FLOWS
3.1
General
Most of the water requirements in the Orange River Basin are supplied through two major
water supply systems i.e. the Integrated Vaal River System and the Orange River Project
(Gariep and Vaderkloof dams). Several transfer schemes are in place to augment the Vaal
River (See Figure A-3 in Appendix A) as the demand within the Vaal River basin by far
exceeds the water available from the Vaal River alone. A simplified schematic of the
Integrated Vaal River and Orange River system is shown in Figure 3.1. From this figure all
the transfers from other sub-systems to the main Vaal System as well as from the Orange
River to other sub-systems are clearly shown. Within the Vaal River System there are
numerous smaller sub-systems which are operated as individual stand alone schemes
used to supply local requirements. These sub-systems are not used to support the main
Vaal River System, but affect the yield of the main system due to the reduced base flow in
the tributaries and spills from the sub-system reservoirs.
The Orange River originates in the Lesotho Highlands where it is known as the Senqu
River and only when it enters the RSA is it referred to as the Orange River. In contrast to
the Vaal River System the Orange River System is used to support users in neighbouring
catchments (See Figure A-4 in Appendix A and Figure 3.1). From the Lesotho Highlands
Project (Katse and Mohale dams) water is transferred to the Vaal System to augment Vaal
Dam, from Gariep Dam water is transferred via the Orange/Fish tunnel to the Eastern
Cape mainly in support of irrigation, from Vanderkloof Dam water is transferred to the
Riet/Modder catchment also mainly for irrigation purposes and finally from Welbedacht and
Knellpoort dams in the Caledon River catchment water is transferred to the Modder River
catchment to supply urban/industrial requirements of Bloemfontein, Botchabelo and
others. Within the greater Orange River System various smaller sub-systems are found
which are also operated as individual stand alone schemes not used to support the
Orange River Project, similar to those in the Vaal River System. These sub-systems are
not all located in the RSA but several are located in Namibia, with some in Lesotho and
none in Botswana, except for the groundwater use in Botswana.
It was therefore decided to split this section into five main sections i.e. the Vaal River
System, the Orange River System, sub-systems in Namibia, sub-systems in Lesotho and
the water demands in Botswana.
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Figure 3-1: Simplified schematic of the Integrated Vaal River and Orange River
system
3.2
Vaal River System (RSA)
3.2.1
Main system
Being the principal source of water supply to Gauteng, the Vaal River system is perhaps
South Africa's most important system, but certainly the most over-utilised river system.
The Main Vaal River System comprises of four major storage dams in the Vaal River
Basin, i.e. the Grootdraai Dam, Sterkfontein Dam, Vaal Dam and Bloemhof Dam (See
Figures A-1 & A-5 in Appendix A).
Grootdraai Dam is used to supply Standerton, Sasol II & III, Tutuka Power station as well
as part of the water requirement of Duvha, Matla, Kendal and Kriel power stations located
in the Olifants River catchment. Grootdraai Dam is supported by transfers mainly from
Heyshope Dam in the Assegaai River but also to a lesser extent from Zaaihoek Dam in the
Slang River located within the Thukela catchment.
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Sterkfontein Dam is located in the upper reaches of the Wilge River a tributary of the Vaal
River, and stores the water transferred from Woodstock Dam and Driel Barrage in the
Thukela River. Sterkfontein Dam is mainly used to support Vaal Dam, as and when
required. This support only occurs when Vaal Dam is at very low levels.
Vaal Dam and Vaal Barrage are located at the downstream end of the Upper Vaal
catchment and are used to supply Gauteng with water. Water is also released from Vaal
Dam to support users between Vaal Dam and Bloemhof Dam as well as to support
Bloemhof Dam with water. The main users between Vaal Dam and Bloemhof Dam include
Rand Water, Sasol 1, Midvaal WC, Sedibeng Water and irrigation along the Vaal River.
The Vaalharts Irrigation Scheme is the main user in the Lower Vaal WMA and is supplied
with water from Bloemhof Dam. Water is released from Bloemhof Dam into the river and is
diverted into the Vaalharts main canal at the Vaalharts Weir. Releases from Bloemhof
Dam are also used to supply water to Kimberley, the Vaal Gamagarra Water Supply
Scheme as well as irrigation along the Vaal River between Bloemhof Dam and the
conluence of the Vaal and Riet River.
The demands imposed on the main Vaal System are summarised in Table 3.1 with details
given in the excel data base. The total demand imposed on the main Vaal System is
2 790 million m3/a in 2005 and increases over time to 3 212 million m3/a by 2025. This
excludes the ecological requirement as it is a non consumptive requirement, but do include
the river evaporation requirements. The ecological requirements are based on desktop
estimates recently determined by the DWAF (RSA) RDM office, using the DSS program
(DWAF, 2006c). These environmental requirements are only first order indications of what
the ecological reserve will be, and are thus currently not supplied by means of any
releases from the reservoirs.
Table 3-1: Demands imposed on the main Vaal River System
Demand (million m3/a) for given year
Description
2005
2015
2025
Urban/Industrial
Rand Water
1 307.86
1 498.48
1 665.23
Sedibeng
40.95
41.33
41.92
Midvaal CO
35.00
35.00
35.00
Others
59.25
80.94
80.77
Sub-total
1 443.06
1 638.59
1 804.10
Mining
29/11/2007
Final
17

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Orange IWRMP
Task 8: Water Requirements
Vaalreefs
1.54
1.82
2.15
Sub-total
1.54
1.82
2.15
Power Stations
Supplied from Vaal only
101.02
131.19
140.17
Supplied partially from Vaal
125.12
154.93
157.04
Sub-total
226.43
286.12
297.21
Strategic Industries
Sasol
116.29
137.94
153.94
Mittal Steel
17.35
16.62
16.62
Sub-total
133.64
154.56
170.56
Irrigation
Vaalharts
327.80
327.80
327.80
Other
210.49
162.63
162.63
Sub-total
538.29
490.43
490.43
Rural
Vaal Gamagara scheme
13.70
13.70
13.70
Sub-total
13.70
13.70
13.70
Losses
Canal
127.02
127.02
127.02
Transfers
40.10
40.10
40.10
Operational
115.35
115.35
115.35
Other
73.75
73.75
73.75
356.22
356.22
356.22
Ecological Requirements
Ecological requirement **
737.45
737.45
737.45
River evaporation requirement
78.1
78.1
78.1
Total for Main Vaal System*
2790.77
3019.54
3212.47
Note
*: The total excludes the ecological requirement as it is a non consumptive demand
**: This represents the ecological requirement at the downstream end of the Vaal River at Douglas
Rand Water is by far the largest water user from the Main Vaal System, utilising
approximately 47% of the total demand imposed on the Main Vaal System. The Rand
Water supply area is located partly in the Vaal River catchment (51% on a demand basis)
and the rest to the North mainly in the Crocodile West River catchment (49% on a demand
basis). This means that approximately half of the return flows generated from the urban
industrial area wil not flow back into the Vaal River basin but will in fact be transferred to
the Crocodile West River basin.
The water demand growth projections were obtained from the `'Vaal River System: Large
Bulk Water Supply Reconciliation Strategy'' study (DWAF,2006a & b), which is the latest
projections available. Several growth projection scenarios are given in the `'First Stage
Reconciliation Strategy'' report (DWAF, 2006a) from the Vaal Reconciliation Study and the
29/11/2007
Final
18

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Orange IWRMP
Task 8: Water Requirements
most likely scenario, referred to as Scenario B was selected for the purpose of this study.
Scenario B is based on the August 2006 population estimate of Stats RSA and excludes
the effects of water conservation and water demand management options, but includes the
expected eradication of unlawful irrigation use.
The decrease in the irrigation projections is therefore due to the expected eradication of
unlawful irrigation mainly in the Upper Vaal WMA.
The process of validation and
verification of existing registered irrigation water use is currently still ongoing in the Vaal
River basin, and actions with regards to the eradication of unlawful use can only
commence, once it has been completed.
Monthly Requirements
In system yield analysis it is of importance to include the monthly distribution pattern of the
demands as it also affects the yield available from a system. If the monthly demand
pattern is in phase with the monthly runoff distribution, the system will be able to produce a
slightly higher yield than one would have if the distribution pattern is totally out of phase. In
the case of irrigation demands, one normally has a higher variation in the monthly demand
distribution than with typical urban industrial demands. Irrigation demands in general also
vary considerably from year to year. During wet years less irrigation water is required due
to the higher contribution from rainfall and during dry years a higher irrigation demand is
required due to low rainfall. This high irrigation requirement also occurs during the critical
period of the reservoir yield analysis, and therefore decreases the available yield.
Monthly distribution of various demands imposed on the Vaal System and sub-systems
are summarised in Table 3.2.
29/11/2007
Final
19

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Orange IWRMP
Task 8: Water Requirements
Table 3-2: Examples of monthly demand distributions for demands within the Vaal River catchment for 1994
development
Monthly and annual requirement (million m³)
Channel No
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Annual
Urban abstractions from Suikerbosrant River East
0.25 0.33 0.36 0.41 0.38 0.40 0.49 0.49 0.46 0.42 0.45 0.40
4.81
Daggafontein, Marievale and Ergo Daggafontein
Klerkskraal Dam Irrigation demand
2.35 2.12 2.18 2.15 1.89 2.22 2.09 1.99 1.98 2.08 2.08 2.24
25.38
Boskop Dam Irrigation demand
5.06 4.26 4.68 4.95 4.10 4.24 3.66 3.88 3.50 4.11 4.64 5.14
52.23
Klipdrift Dam Irrigation demand
0.54 0.33 0.30 0.57 0.48 0.43 0.31 0.28 0.23 0.35 0.58 0.58
5.00
Demand supplied from Koppies Dam mainly irrigation
1.07 0.72 0.71 1.03 0.83 0.84 0.57 0.71 0.26 0.48 1.32 1.38
9.92
Allemanskraal Dam Irrigation demand
4.20 2.70 2.49 3.27 2.77 3.01 1.55 1.39 1.82 1.98 3.24 4.02
32.44
Erfenis Dam Irrigation demand
5.07 3.50 3.05 3.97 3.03 3.18 1.79 1.95 2.29 2.65 3.90 4.90
39.28
Mine return flow to Boskop Dam
1.74 1.69 1.66 1.81 1.38 1.64 1.36 1.52 1.27 1.52 1.40 1.26
18.25
29/11/2007
Final
20

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Orange IWRMP
Task 8: Water Requirements
3.2.2
Smaller sub-systems within the Vaal River Basin
The total demand imposed on the smaller sub-systems within the Vaal River Basin
accumulates to a significant volume of 1 055 million m3/a, for the year 2005.
This
comprises of almost 25 percent of the total water demand in the basin. The focus on
water supply in the smaller subsystems is on irrigation with almost 64 percent of the total
demand allocated to irrigation. Excluding the Vaalharts Irrigation Scheme, which receives
water from the main Vaal System, there are another twelve irrigation schemes located in
the tributary catchments of the Vaal River. These irrigation schemes contribute to only 35
percent of all the irrigation in the smaller sub-systems, at the 2005 development level. The
rest of the irrigation is referred to as diffuse irrigation, as it is typically irrigation that is
scattered all over the river basin, and which is not part of an organised irrigation scheme.
The bulk of this irrigation is located in the Upper Vaal and Vaal Barrage catchments.
Based on the preliminary findings of the current validation and verification studies, it
seems that a large portion of this irrigation is unlawful. The unlawful irrigation needs to be
eradicated, which is the reason for the decrease in the irrigation demand projection
between the years 2005 and 2015. The process of the elimination of unlawful irrigation will
most probably start as soon as the validation and verification of water use in the Upper
Vaal WMA has been completed.
Table 3-3: Demands imposed on the smaller systems within the Vaal River Basin
Demand (million m3/a) for given year
Description
2005
2015
2025
Urban/Industrial
Bloemfontein & Botchabelo
68.76
78.10
90.80
Kroonstad & Lindley
12.29
11.76
10.52
Potchefstroom
15.49
17.16
18.82
Others
59.60
60.74
60.85
Sub-total
156.14
167.76
180.99
Mining
Balfour & Ergo
5.95
6.22
6.35
Sub-total
5.95
6.22
6.35
Power Stations
Majuba supplied from Zaaihoek
19.19
25.58
24.15
Sub-total
19.19
25.58
24.15
Rural Domestic Requirements
Upper Vaal
9
9
9
Vaal Barrage
1.2
1.2
1.2
Middle Vaal
5.6
5.6
5.6
29/11/2007
Final
21

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Orange IWRMP
Task 8: Water Requirements
Demand (million m3/a) for given year
Description
2005
2015
2025
Lower Vaal
3.16
3.16
3.16
Riet-Modder
1
1
1
Sub-total
19.96
19.96
19.96
Livestock
Upper Vaal
34
33
32
Vaal Barrage
4.3
4.3
4.3
Middle Vaal
35.9
35.9
35.9
Lower Vaal
25.58
25.58
25.58
Riet-Modder
12
12
12
Sub-total
111.78
110.78
109.78
Irrigation
Irrigation Schemes
Allemanskraal Irrigation
36.99
36.99
36.99
Boskop Irrigation
28.59
28.59
28.59
Erfenis Irrigation
39.28
39.28
39.28
Klerkskraal Irrigation
6.66
6.66
6.66
Klipdrift Irrigation
7.12
7.12
7.12
Klerksdorp Irrigation
10.25
10.25
10.25
Koppies Irrigation
5.8
5.8
5.8
Schoonspruit Irrigation
18.68
18.68
18.68
Spitskop Irrigation
12.81
12.81
12.81
Kalkfontein Canal Scheme
33.5
33.5
33.5
Tierpoort Irrigation Scheme
6.4
6.4
6.4
Modder River G.W.S.
29.4
29.4
29.4
Sub-total
235.48
235.48
235.48
Diffuse Irrigation
Upper Vaal
183.85
61.93
61.93
Vaal Barrage
70.35
25.28
25.28
Middle Vaal
87.54
80.28
80.28
Lower Vaal
9.52
9.52
9.52
Riet-Modder
85.4
85.4
85.4
Sub-total
436.66
262.41
262.41
Sub-total
672.14
497.89
497.89
Losses
Mine dewatering
13.80
13.80
13.80
Caledon/Modder transfer & system
12.40
12.40
12.40
Weltand & bedlosses
44.11
44.11
44.11
Sub-total
70.31
70.31
70.31
Ecological Requirements **
Allemanskraal Dam
15.38
15.38
15.38
Boskop Dam
20.24
20.24
20.24
Erfenis Dam
16.75
16.75
16.75
29/11/2007
Final
22

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Orange IWRMP
Task 8: Water Requirements
Demand (million m3/a) for given year
Description
2005
2015
2025
Klipdrift Dam
3.37
3.37
3.37
Koppies Dam
10.98
10.98
10.98
Johan Neser Dam
11.62
11.62
11.62
Spitskop Dam
23.22
23.22
23.22
Tweerivier
72.15
72.15
72.15
Total for the sub-systems in Vaal
1 055.47
898.50
909.43
Note *: The total excludes the ecological requirement as it is a non consumptive demand
**: These represent the ecological requirement at the downstream end of the sub-systems
The total groundwater use within the Vaal River basin is estimated at 215 million m3/a at
1995 development level. The bulk of the groundwater use is taking place in the Lower
Vaal WMA (45% of total use) followed by the Middle Vaal WMA with almost 33% of the
total groundwater use. All the demands listed in Table 3.3 are supplied from surface water
resources, with the exception of the rural domestic and livestock water requirements,
which are mainly supplied from groundwater.
3.2.3
Return flows
Most of the return flows generated in the Vaal River basin originate from the Southern
Gauteng urban/industrial area which is supplied by Rand Water.
For this area,
approximately 51% of the gross demand returns to the Vaal River. The return flows from
the Northern Gauteng area flows into the Crocodile West River basin. Approximately 49%
of the demand in the Northern Gauteng ends up as return flows in the Crocodile River
basin, reaching a volume of almost 270 million m3/a in the year 2005.
Mine dewatering mainly takes place in the catchment between Vaal Dam, and the
confluence of the Vaal and Schoonspruit rivers. The volumes from mine dewatering is
significant and already accumulated to a total of 114 million m3/a in the year 2005.
As result of the highly populated and industrialised Gauteng area, increased runoff due to
paved areas reached a volume of approximately 100 million m3/a in 2005. A summary of
the return flows from the urban, industrial and mining sectors are given in Table 3.4.
29/11/2007
Final
23

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Orange IWRMP
Task 8: Water Requirements
Table 3-4: Summary of Urban/Industrial and Mining related return flows
Return flows (million m3/a) for given year
Description
2005
2015
2025
Southern Gauteng (Rand Water)
335
392
438
Midvaal Water Company
1
1
1
Sedibeng Water
2
2
2
Other towns and industries
85
97
107
Mine dewatering
114
121
121
Increased urban runoff
101
107
121
Total
638
720
790
Return flows from irrigation is generally in most studies assumed to be in the order of 10%
of the irrigation demand. This is not always true as it is dependant on several factors such
as the soil type, location of the irrigation fields, type of irrigation system used, type and
condition of the main distribution system, management practices, etc. More detailed
analyses on return flows from the main irrigation schemes in the Vaal River Basin were
recently undertaken as part of the Vaal River Reconciliation study (DWAF,2006b), which
resulted in return flows varying between 4% to 22% (See Table 3.5).
Table 3-5: Return flows from main irrigation schemes
Gross inflow
Return flows
Percentage
Irrigation Scheme
(million m³/a)
(million m³/a)
Return flow
Vaalharts Scheme
392.95
49.03
12
Klerksdorp Scheme
4.93
0.25
5
Schoonspruit Scheme
24.10
5.31
22
Mooi River Scheme
165.50
97.08
*59 (4)
(71 38)*
(2 96)*
(4)*
Erfenis Canal Scheme
43.92
3.89
9
Erfenis River Scheme
9.76
0.38
4
Allemanskraal Canal Scheme
40.56
6.63
16
Total
681.72
162.57
24
(589.60)*
(68.45)*
(12)*
Notes:*- A very high percentage of the Mooi River Scheme return flows is as result of the large volume of tail
water flow from the canal end. When the effect of the tail water flow is removed the result is given by the value
in brackets.
29/11/2007
Final
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Orange IWRMP
Task 8: Water Requirements
3.3
Orange River System
3.3.1
The Main Orange System (Mainly RSA)
The Main Orange System consists of two major storage dams, i.e. Gariep and Vanderkloof
Dam (See Figures A-1 & A-6 in Appendix A). This system is also referred to as the
Orange River Project (ORP). Gariep Dam with a gross storage of 5 342 million m3 is the
largest storage dam in the Orange River Basin and Vanderkloof Dam with a gross storage
of 3 186 million m3 the second largest. The two dams are used to supply all the demands
along the Orange River from Gariep Dam to the Orange River mouth. These demands
include all the irrigation, urban, mining, environmental requirements, river evaporation
requirements and operational losses. Large volumes of water are also transferred from
the two dams to neighbouring catchments (See Figure A-4). These transfers include the
following:
· The transfer through the Orange-Fish tunnel from Gariep Dam to the Eastern
Cape to support large irrigation developments, as well as some urban/industrial
requirements.
· The transfer through the Orange-Riet canal from Vanderkloof Dam to the Riet-
Modder catchment, mainly for irrigation purposes.
· Orange-Vaal transfer from the diversion weir at Marksdrift in the Orange River
downstream of Vanderkloof Dam. Water is diverted into a canal from Marksdrift
Weir to Douglas Weir in the Lower Vaal River just before the confluence of the
Vaal and Orange rivers. This scheme mainly supply water for irrigation purposes
and is also used to improve the water quality in the Douglas Weir at the
downstream end of the Vaal River.
· Relatively small transfer from the Lower Orange along the common border
between the RSA and Namibia. This transfer is used to supply water to the towns
of Springbok and Kleinsee, for urban and mining purposes.
Water is released directly into the Orange River from Gariep and Vanderkloof Dams to
supply all the downstream users.
These river releases are used to simultaneously
generate hydropower for Eskom. Only the transfers through the Orange-Fish tunnel and
through the Orange-Riet canal are not part of the releases into the river, and can therefore
not be used to generate hydropower. At times when there is surplus water available in the
29/11/2007
Final
25

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Orange IWRMP
Task 8: Water Requirements
two major dams, the surplus is utilised to generate hydropower. During times when
spillage occurs from the dams the maximum possible flow is routed through the turbines,
to generate hydropower.
A summary of the demands imposed on the Orange River main system (Orange River
Project) is given in Table 3.6, with details provided in the excel data base. The total
demand imposed on the main Orange System is 3 250 million m3/a in 2005 and increases
over time to 3 652 million m3/a by 2025. This includes the ecological requirement of 289
million m3/a, which is currently released from Vanderkloof Dam, but excludes the high
ecological requirement of 1 062 million m3/a on average, as obtained from preliminary
work done in the Lower Orange River Management Study (LORMS) (PWC,2004). The
results from the LORMS were obtained from using the latest technology available in this
regard, although it was done at an intermediate level of detail. The LORMS result will be
closer to the final expected ecological reserve that must still be determined and
implemented.
Irrigation is by far the largest water use sector in the Main Orange System using almost
60% of the total demand imposed on the ORP. Losses represent approximately 10% of
the total demand, and the operational loss is the largest loss component. The high
operational loss is due to the long distance of approximately 1 300km over which the
demands are spread along the Orange River and supplied with releases from Vanderkloof
Dam. It takes on average, 1 month for the releases to reach the most downstream users.
Although there is a separate section on the Namibian water requirements, some of the
Namibia water requirements are included in Table 3.6 as they are supplied from the ORP.
Table 3-6: Demands imposed on the main Orange River System (Orange River
Project)
Demand (million m3/a) for given year
Description
2005
2015
2025
Urban/Industrial/Mining
RSA
Orange-FishTransfer (Eastern Cape)
20.00
20.00
41.30
Orange-Riet Transfer
0.30
0.40
0.50
Orange Vaal Transfer
1.20
1.40
1.70
Upper Orange
2.10
2.30
2.50
Lower Orange
36.10
47.20
47.90
Springbok-Kleinsee transfer
4.60
5.60
6.90
29/11/2007
Final
26

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Orange IWRMP
Task 8: Water Requirements
Sub-total RSA
64.30
76.90
100.80
Namibia
Directly from river in common border
15.92
46.72
47.69
Sub-total Namibia
15.92
46.72
47.69
Sub-total urban/industrial/mining
80.22
123.62
148.49
Irrigation
RSA
Orange-FishTransfer (Eastern Cape)
607.30
651.00
651.00
Orange-Riet Transfer
183.80
183.80
183.80
Orange Vaal Transfer
80.20
80.20
80.20
Upper Orange
84.40
84.40
84.40
Upper Orange Growth
0.00
44.00
44.00
Lower Orange
936.00
936.00
936.00
Lower Orange Growth
0.00
60.00
60.00
Sub-total RSA
1 891.70
2 039.40
2 039.40
Namibia
Current along common border
62.70
62.70
62.70
Growth along common border
0.00
94.80
175.30
Sub-total Namibia
62.70
157.50
238.00
Sub-total Irrigation
1 954.00
2 092.80
2 173.30
Losses
Canal
27.00
27.00
27.00
Transfers
34.70
34.70
34.70
Operational
270.00
270.00
270.00
Sub-total
331.70
331.70
331.70
Ecological Requirements
Ecological requirement *
1 062.00
1 062.00
1 062.00
Currently released &
288.90
288.90
288.90
River evaporation requirement
615.00
615.00
615.00
Sub-total
903.90
903.90
903.90
Power Stations
Hydro Power at Gariep &
Utilises releases to meet downstream requirements for hydro
Vanderkloof dams
power generation purposes. Only when surplus water is
available, will additional water be allocated for power
generation purposes
Total for Main Orange System*
3 270.32
3 556.22
3 661.60
Note : * - The total excludes the ecological requirement of 1 062 as it represents the average flow
required
at the river mouth. This is an indication of what the reserve should be and is not
currently supplied.
& - This is the volume currently released from Vanderkloof Dam for ecological purposes.
Results from the LORMS (PWC, 2004) indicated that the operational losses can be
reduced by approximately 80 million m3/a when real time modelling is introduced to
29/11/2007
Final
27

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Orange IWRMP
Task 8: Water Requirements
improve the control and management of releases from Vanderkloof Dam. A re-regulating
dam at Vioolsdrift can reduce these losses by approximately 170 million m3/a.
The river evaporation and evapo-transpiration (from natural vegetation) requirement along
the Orange River downstream of Vanderkloof Dam accumulates to a significant volume of
615 million m3/a, or 19% of the total demand. This is a natural water requirement and
forms part of the ecological requirements.
The urban/industrial/mining requirement along the Orange River is relative small and
comprises of only 2.5% of the total demand.
Monthly Requirements
In system yield analysis it is of importance to include the monthly distribution pattern of the
demands as it also affects the yield available from a system. If the monthly demand
pattern is in phase with the monthly runoff distribution, the system will be able to produce a
slightly higher yield than one would have if the distribution pattern is totally out of phase. In
the case of irrigation demands, one normally has a higher variation in the monthly demand
distribution than with typical urban industrial demands. Irrigation demands can also vary
considerably from year to year. During wet years, less irrigation is required due to the
higher contribution from rainfall and during dry years, a higher irrigation demand is
required due to low rainfall. This high irrigation requirement also occurs during the critical
period of the reservoir yield analysis, and therefore decreases the available yield.
Monthly distribution of various demands imposed on the greater Orange River System is
summarised in Table 3.7.
29/11/2007
Final
28

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Orange IWRMP
Task 8: Water Requirements
Table 3-7:Monthly Demands distribution for demands within the greater Orange River System at 2005 Development
Levels (million cub. m/a)
DESCRIPTION
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT ANNUAL
AREA 1 UPSTREAM OF GARIEP
CALEDON RSA URB DMD
0.350
0.350
0.350
0.350
0.350
0.350 0.350 0.350 0.350 0.350 0.350
0.350 4.200
URBAN DMD KRAAI NODE
0.892
0.892
0.892
0.892
0.892
0.892 0.892 0.892 0.892 0.892 0.892
0.892 10.700
CALEDON LESOTHO URBAN DMD
0.917
0.917
0.917
0.917
0.917
0.917 0.917 0.917 0.917 0.917 0.917
0.917 11.000
BOTSHABELO DMD
1.264
1.264
1.264
1.264
1.264
1.264 1.264 1.264 1.264 1.264 1.264
1.264 15.169
BLOEMFONTEIN DMD
4.243
4.298
4.564
5.011
4.034
3.901 3.424 3.448 3.221 3.358 3.815
4.112 47.430
LHWP TRANSFER
65
65
65
65
65
65
65
65
65
65
65
65
780
AREA 2 GARIEP TO ORANGE/VAAL CONFLUENCE
ORANGE RIVER IRR: (Vanderkloof to Torquay)
19.386 3.295
4.801
12.614 9.799
13.413 11.244 1.338 4.712 6.703 11.922 17.471 116.70
HOPETOWN DMD
0.167
0.167
0.167
0.167
0.167
0.167 0.167 0.167 0.167 0.167 0.167
0.167 2.000
ORANGE RIVER EVAPORATION REQUIREMENTS
4.6294 5.7038 6.2015 6.1857 4.6294 3.7051 2.5122 1.9039 1.3667 1.58
2.3305 3.5076 44.2558
REACH 1a
DOUGLAS DMD
0.100
0.100
0.100
0.100
0.100
0.100 0.100 0.100 0.100 0.100 0.100
0.100 1.200
IRR FROM DOUGLAS WEIR & CANAL
13.294 3.347
4.033
6.642
4.219
3.850 2.975 0.650 3.117 4.399 7.764
11.409 65.70
RICHIE URB
0.025
0.025
0.025
0.025
0.025
0.025 0.025 0.025 0.025 0.025 0.025
0.025 0.300
RAMAH & VANDERKLOOF IRR
9.252
3.177
4.723
8.030
4.299
4.829 3.975 0.681 2.176 3.062 5.388
7.910 57.502
GARIEP TO VANDERKL URBAN
0.175
0.175
0.175
0.175
0.175
0.175 0.175 0.175 0.175 0.175 0.175
0.175 2.100
ORANGE RIVER IRR: (Torquay to Orange-Vaal Confl.)
5.997
1.019
1.485
3.902
3.031
4.150 3.478 0.414 1.458 2.073 3.688
5.405 36.10
ORANGE RIVER LOSSES REACH 1b
1.2306 1.5162 1.6485 1.6443 1.2306 0.9849 0.6678 0.5061 0.3633 0.42
0.6195 0.9324 11.7642
29/11/2007
Final
29

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Orange IWRMP
Task 8: Water Requirements
DESCRIPTION
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT ANNUAL
TOTAL SYSTEM OPERATING LOSSES
15.89
15.38
15.89
15.89
14.53
34.16 50.65 34.16 21.67 20.23 15.89
15.64 270.00
AREA 3 RIET/ MODDER
THABA N'CHU DMD
0.267
0.267
0.267
0.267
0.267
0.267 0.267 0.267 0.267 0.267 0.267
0.267 3.200
KALKFONTEIN URBAN DEM
0.142
0.142
0.142
0.142
0.142
0.142 0.142 0.142 0.142 0.142 0.142
0.142 1.700
AREA 4 ORANGE RIVER : ( Orange/Vaal confl. to 20 degree
Longitude)
PRIESKA URB
0.161
0.186
0.208
0.249
0.202
0.198 0.159 0.138 0.135 0.118 0.131
0.143 2.027
ORANGE RIVER EVAPORATION REQUIREMENTS
13.22
16.31
17.72
17.67
13.22
10.59 7.19
5.44
3.9
4.5
6.67
10.02 126.45
REACH 2
IRR MID ORANGE
22.434 3.814
5.556
14.597 11.339 15.523 13.012 1.549 5.453 7.757 13.796 20.219 135.048
UPINGTON RIVER IRR ABS.
7.242
8.280
10.096 13.617 7.021
4.573 3.008 0.462 1.408 1.768 2.636
3.932 64.043
KAKEMAS RIVER IRR ABS
3.558
4.703
5.147
6.573
3.119
2.122 1.435 0.114 0.770 0.918 1.224
1.797 31.480
BOEGOEBERG IRR
11.543 13.197 16.092 21.703 11.190 7.289 4.794 0.736 2.244 2.819 4.202
6.267 102.076
UPINGTON IRR
11.566 13.574 15.694 20.991 10.660 7.515 5.132 0.636 2.387 2.951 4.255
6.307 101.669
KEIMOES IRR
7.329
8.601
9.944
13.300 6.754
4.761 3.252 0.403 1.513 1.870 2.696
3.997 64.419
ORANGE RIVER EVAPORATION REQUIREMENTS
13.68
16.87
18.34
18.28
13.68
10.96 7.44
5.63
4.04
4.66
6.9
10.37 130.85
REACH 3
KAKEMAS URB DMD
0.193
0.232
0.265
0.288
0.256
0.228 0.170 0.153 0.141 0.141 0.152
0.162 2.380
KAKEMAS IRR DMD
12.013 15.880 17.377 22.193 10.531 7.163 4.844 0.383 2.600 3.098 4.134
6.068 106.284
ORANGE RIVER EVAPORATION REQUIREMENTS
3.88
4.78
5.2
5.18
3.88
3.11
2.11
1.6
1.15
1.32
1.96
2.94
37.11
REACH 4
UPINGTON AND OTHERS URB DMD
1.432
1.722
1.971
2.143
1.902
1.692 1.262 1.133 1.045 1.047 1.126
1.204 17.680
29/11/2007
Final
30

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Orange IWRMP
Task 8: Water Requirements
DESCRIPTION
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT ANNUAL
NAMAQWALAND IRR U/S NAMIBIA
1.105
1.461
1.599
2.042
0.969
0.659 0.446 0.035 0.239 0.285 0.380
0.558 9.779
AREA 5 ORANGE RIVER : ( 20 °Longitude to river mouth)
RSA
NAMAQWALAND IRR D/S NAMIBIA
4.014
4.902
5.916
7.635
3.738
2.106 1.279 0.278 0.768 0.952 1.398
2.109 35.096
URB. DMD SPRINBOK AND PELLADRIFT
0.391
0.448
0.442
0.474
0.476
0.423 0.389 0.344 0.328 0.317 0.335
0.373 4.740
VIOOLSDRIFT AND MINOR IRR
0.771
1.209
1.529
2.059
1.004
0.269 0.156 0.094 0.058 0.071 0.113
0.194 7.528
ALEXANDER BAY IRR
1.104
0.640
0.681
1.500
1.146
1.490 1.225 0.226 0.249 0.338 0.578
0.870 10.045
SPRINGBOK OR NAMAKWA WATER BOARD
0.345
0.389
0.450
0.482
0.471
0.402 0.403 0.378 0.316 0.327 0.345
0.291 4.600
URB.DMD. ALEX.BAY
0.608
0.608
0.608
0.608
0.608
0.608 0.608 0.608 0.608 0.608 0.608
0.608 7.300
AREA 5 ORANGE RIVER : ( 20 °Longitude to river mouth) Namibia
PELLADRIF NAMIBIA IRR
2.151
2.626
3.169
4.089
2.002
1.128 0.685 0.150 0.411 0.510 0.749
1.129 18.80
VIOOLSDRIF NAMIBIA IRR
1.997
3.132
3.962
5.334
2.600
0.697 0.404 0.244 0.151 0.185 0.292
0.502 19.50
ORANJEMUND & ROSH PINAH
0.705
0.746
0.662
1.040
0.748
0.739 0.729 0.571 0.581 0.538 0.639
0.582 8.280
HAIB MINE
0.000
0.000
0.000
0.000
0.000
0.000 0.000 0.000 0.000 0.000 0.000
0.000 0.000
ARIAMSVLEI ETC.
0.000
0.000
0.000
0.000
0.000
0.000 0.000 0.000 0.000 0.000 0.000
0.000 0.000
NOORDOEWER, ASSENKEHR
0.014
0.016
0.014
0.021
0.018
0.015 0.015 0.012 0.011 0.010 0.011
0.012 0.170
MINES ROSH PINAH ETC.
0.571
0.571
0.571
0.571
0.571
0.571 0.571 0.571 0.571 0.571 0.571
0.571 6.850
AREA 5 ORANGE RIVER : ( 20 degree Longitude to river mouth)Combined RSA and Namibia
ORANGE RIVER EVAPORATION REQUIREMENT REACH 15.05 18.55 20.17 20.1
15.05
12.05 8.19
6.19
4.45
5.13
7.59
11.4
143.92
5
ORANGE RIVER EVAPORATION REQUIREMENT REACH 5.67
6.99
7.6
7.57
5.67
4.54
3.08
2.33
1.67
1.93
2.86
4.29
54.2
6
29/11/2007
Final
31

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Orange IWRMP
Task 8: Water Requirements
DESCRIPTION
OCT
NOV
DEC
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT ANNUAL
ORANGE RIVER EVAPORATION REQUIREMENT REACH 6.95
8.57
9.32
9.29
6.95
5.57
3.78
2.86
2.06
2.37
3.51
5.27
66.5
7
RIVER MOUTH ENVIRONMENTAL + IFR (Currently
32.141 31.104 32.141 32.141 29.290 32.141 31.104 24.106 15.552 9.374 9.374
10.368 288.85
released)
AREA 6 NAMIBIA FISH RIVER
HARDAP IRRIGATION
3.711
3.586
3.194
5.717
5.125
3.936 4.170 2.498 1.914 2.081 2.948
2.819 41.700
NAUTE IRRIGATION
0.413
0.399
0.355
0.636
0.570
0.438 0.464 0.278 0.213 0.232 0.328
0.314 4.640
HARDAP URBAN
0.087
0.086
0.083
0.104
0.092
0.081 0.077 0.072 0.065 0.067 0.066
0.069 0.950
NAUTE URBAN
0.159
0.186
0.151
0.220
0.202
0.145 0.174 0.148 0.145 0.124 0.141
0.155 1.950
29/11/2007
Final
32

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Orange IWRMP
Task 8: Water Requirements
3.3.2
Other sub-systems within the Orange River Basin (RSA)
The largest of the other sub-systems within the Orange River basin, is the Lesotho
Highlands Water Project (LHWP), which is used to transfer water to the Integrated Vaal
River System. This transfer has almost reached its maximum of 877 million m3/a. This
volume is continuously transferred to the Vaal System, irrespective of the water situation
and dam levels in the RSA (see Table 3.8). Although the LHWP is located in Lesotho,
details of the transfers are also included in Table 3.8 as it is used to supply water primarily
to the RSA.
Table 3-8: Demands imposed on the other sub-systems within the Orange River
Basin
Demand (million m3/a) for given year
Description
2005
2015
2025
Transfers
LHWP
780
877
877
Caledon/Modder
55
70
83
Sub-total
835
947
960
Urban/Industrial/Mining
Caledon RSA
4.2
4.7
5.2
Upper Orange
10.7
12.8
15.3
Lower Orange
5.96
5.96
5.96
Sub-total
20.86
23.46
26.46
Rural Domestic Requirements
Caledon RSA
0.70
0.70
0.70
Upper Orange
2
2
2
Lower Orange
10.04
10.04
10.04
Sub-total
12.74
12.74
12.74
Livestock
Caledon RSA
6.30
6.30
6.30
Upper Orange
15.2
15.2
15.2
Lower Orange
23.86
23.86
23.86
Sub-total
45.36
45.36
45.36
Irrigation
Caledon RSA
70.4
70.4
70.4
Upper Orange from main river
33.1
33.1
33.1
Upper Orange Diffuse
288.91
288.91
288.91
Lower Orange
11.64
11.64
11.64
Sub-total
404.05
404.05
404.05
Losses
Knelpoort support to Welbedaght
3.70
3.70
3.70
Sub-total
3.70
3.70
3.70
29/11/2007
Final
33

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Orange IWRMP
Task 8: Water Requirements
Demand (million m3/a) for given year
Description
2005
2015
2025
Ecological Requirements **
Matsoku Weir
20.5
20.5
20.5
Katse Dam
65.86
65.86
65.86
Mohale Dam
30.44
30.44
30.44
Total for the sub-systems in Orange*
541.71
559.31
575.31
Note: * - The total excludes ecological requirement and transfers out of the Orange system as the
ecological requirements is not a consumptive demand and the demands supplied by means of the transfers
are already included in the Vaal System demands.
The total demand from the sub-systems in the Orange River basin accumulates to
542 million m3/a, and if transfers are included it increases to 1 322 million m3/a. For the
purpose of this study the total demand for the sub-systems is referred to as 542 million
m3/a, as the demands supplied by means of the transfers from the sub-systems are
already included in the Integrated Vaal River System. Irrigation is the largest water user in
the sub-systems and comprises of 75% of the total demand of 542 million m3/a, followed
by the transfers from the Caledon 55 million m3/a, or 10% of the total demand.
The total water use from groundwater is estimated at 115 million m3/a for the 1995
development level. The bulk of the groundwater use (59%) is located in the Lower Orange
where surface water resources are limited beyond the Orange River itself. Most of the
demands listed in Table 3.8 are supplied from surface water resources. The only
exception is the rural domestic and livestock water requirements, which are mainly
supplied from groundwater resources.
Hydro-power is generated by means of the releases from Gariep and Vanderkloof dams to
supply the downstream requirements. This is therefore a non-consumptive demand, and
is not added to the total demand. Only during times when there is a surplus short-term
yield available from Gariep and Vanderkloof dams, is the surplus allocated to Escom to
generate additional hydro-power over and above that generated by means of the normal
releases. Currently the total demand imposed on the main Orange System, has reached
the long-term yield available from the Orange River Project, and surplus conditions very
seldom occur. During periods when the dams are spilling, the maximum possible volume is
released through the hydro-power turbines, to utilise the spills far as possible for this
purpose.
29/11/2007
Final
34

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Orange IWRMP
Task 8: Water Requirements
3.3.3
Return flows
The return flows from the Urban/Industrial and mining sector is relatively small in the
Orange River Basin. Some of the water supply systems such as Pelladrift and Namakwa
supply water to towns located far from the Orange River and return flows will not reach the
river. Most of the smaller towns, direct their return flows to evaporation ponds or pan
areas, preventing these flows to return to the main river. The mines re-circulate their water
to a large extent and their waste water is generally evaporated through evaporation ponds.
Bearing in mind that the urban industrial demand in the Orange only represents 2.5% of
the total Orange demand, the return flows from this sector are negligible.
Return flows from irrigation are however a considerable amount. The total expected return
flow to reach the Orange River is in the order of 200 million m3/a. These return flows are
to a large extent used by irrigators further downstream along the Orange River, and results
in less water being released from Vanderkloof Dam.
Table 3-9: Return flow estimations from main irrigation areas
Gross demand
Return flows
Percentage
Irrigation area/scheme
(million m³/a)
(million m³/a)
Return flow
Irrigation from Orange & Caledon
112
8
7%
rivers u/s of Gariep Dam
Irrigation from ORP: Gariep to
570
46
8%
Orange Vaal confluence
Irrigation from ORP: Orange Vaal
777
134
17%
confluence to Namibian border
Irrigation from ORP: Orange
111
19
17%
along the RSA / Namibian border
Irrigation from ORP: Eastern
Cape Rivers supplied through
747
261
35%
Orange/Fish tunnel.
Total*
1 570
207
13%
Notes:*- Return flows from the Eastern Cape irrigation is not included in the total as it has no effect on
the flows in the Orange River.
29/11/2007
Final
35

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Orange IWRMP
Task 8: Water Requirements
The irrigation return flows from the Sundays and Fish River in the Eastern Cape will
obviously not contribute to flow in the Orange River, although these irrigation areas are
supplied from the ORP.
3.4
Namibia Water Requirements
3.4.1
Background
In the year 2000 an analysis was done of the present and future water demand in Namibia
and the information in that report will be used to provide an overview of the present and
future water requirements of Namibia within the Orange River Basin.
The Orange River basin covers an area of approximately 260 000 square kilometres in
Namibia and there are three main catchment areas. These ephemeral catchments are the
Fish River and it tributaries (Konkiep, Lowen), the Nossob River and its tributaries (Auob,
Black Nossob, White Nossob, Olifants) as well as the lower Orange which has a number of
seasonal watercourses (Ham, Hom, Haib, Gamchab) flowing into the Orange River along
the common border with South Africa. There is also an endoreic river system, the Oanob
River in the Auob catchment of the Nossob River (See Table 3.10 & Figure A-1 in
Appendix A)
Table 3-10 : Surface area of the Orange River Basin in Namibia
CATCHMENT
SURFACE AREA (km²)
Nossob River
103 858
Fish River
95 680
Orange
60 308
TOTAL
259 846
3.4.2
Population
The Census Office in the National Planning Commission in Namibia carries out a national
population census every ten years, and the last census was completed in 2001. However,
when the water demand report mentioned above was prepared the census statistics were
not yet available and the information of the 1991 census was used to prepare the report.
29/11/2007
Final
36

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Orange IWRMP
Task 8: Water Requirements
At that time it was expected that the increase in the population would generally have been
affected by increasing urbanization from people outside the basin, due to better health
care, and the adverse effects of HIV/AIDS. It was therefore estimated that the population
in the basin would increase from about 156 900 in 1991 to 189 078 in 1999. Based on
those estimates, further estimates were made for the years 2005, 2015 and 2025. It is
therefore estimated that the population will increase from about 202 000 in 2005 to 232
000 in 2025. Please refer to Table 3.11 for the population statistics in the Orange Basin in
Namibia.
According to the 2001 census the number of people in Namibia was about 1 826 900, and
about 174 700 people resided in the Orange Basin. This means that in 2001 about 9,5% of
the Namibian population resided in the Orange Basin.
Table 3-11: Estimated Population in the Orange River Basin in Namibia
POPULATION (Million)
CATCHMENT
1999
2005
2015
2025
Auob
66 962
75 399
80 022
86 177
Fish
64 752
66 791
70 799
76 245
Nossob
37 276
38 450
40 757
43 892
Orange
20 088
22 097
23 754
25 581
TOTAL
189 078
202 737
218 332
231 895
3.4.3
Water Requirements
The water demand in the Orange River Basin in Namibia is mainly due to domestic use in
urban and rural areas, livestock watering on commercial and communal farms, irrigation,
mining and tourism (See Table 3.12).
The domestic water demand in the towns and the rural areas has been based on water
consumption data and projections of the future demand due to the population increase and
the expected improvement in the standard of living. The impact on urbanization due to the
migration of people outside the basin and from the rural areas, better health care and the
adverse effects of HIV/AIDS have been considered in estimating the future domestic water
demand. Namibia is not a highly industrialized country and the industrial water use at
mainly service industries has been included in the urban demand.
29/11/2007
Final
37

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Orange IWRMP
Task 8: Water Requirements
According to the 2001 census the population in the basin was 174 700 people in 2001, but
according to the estimates made on the basis of the 1991 census, the population should
have been 193 500. This means that the urban and rural water demand figures for
domestic use in the water demand report is on the conservative side, but this can be
regarded as insignificant because domestic water use represents only 5, 5% of the total
water demand in the basin.
A comprehensive database of livestock numbers (cattle, donkeys, horses, goats, sheep,
pigs, and ostriches) exists and could be used to determine the number of livestock in the
Orange Basin, as well as the estimated water demand. Due to the limitations in the grazing
capacity of the rangeland, it is not expected that there will be a significant increase in stock
numbers over time, but it will most probably fluctuate around the present number as a
result of the decrease and increase in the availability of grazing due to the seasonal
variations in the rainfall.
There are four main areas where irrigation is practised in the Orange Basin within
Namibia. These are downstream of the Hardap Dam and the Naute Dam where surface
runoff in the ephemeral Fish River basin is used, the Stampriet artesian groundwater basin
underlying the Nossob and Auob catchments where groundwater is used and the irrigation
schemes on farms along the lower Orange River where perennial water is used. The most
notable irrigation schemes are at Noordoewer/Vioolsdrift and Aussenkehr. It is also
anticipated that about 1 000 hectares of land will be brought under irrigation at the
proposed Tandjieskoppe Irrigation Scheme at Noordoewer in the next few years.
The present water requirements for mining purposes at Oranjemund, Rosh Pinah,
Skorpion and a number of small diamond mines along the lower Orange River, as well as
smal mines in the Rehoboth district is known. New mining development is difficult to
anticipate, but the possible development of the proposed Haib copper mine on the lower
Orange River near Noordoewer is on hold until the price of copper has increased to the
extent that mine is economically viable. The proposed development of the Kudu gas power
plant at Oranjemund will also lead to an increase in the water demand, and although
provision has been made for such a demand, it is not clear when the project will actually
come into operation.
29/11/2007
Final
38

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Orange IWRMP
Task 8: Water Requirements
Table 3-12 : Estimated water requirements in the Orange River Basin within Namibia
ESTIMATED DEMAND
CONSUMER
(million m3/a)
GROUP
2005
2015
2025
Urban
14.74
15.97
17.47
Rural
0.317
0.32
0.324
Livestock
16.42
16.82
16.42
Irrigation
118.81
217.32
303.52
Mining
7.35
37.75
38.23
Tourism
0.56
0.69
0.85
TOTAL
158.20
288.47
376.82
A study was done of the water demand in the tourism industry and information was
obtained from bed and breakfast places, guest farms and loges, hotels, resorts and at
camping sites.
The environmental water requirements for the ephemeral watercourses in Namibia and
along the lower Orange River was not included in the assessment of the estimated future
demand by Namibia, Provision has been made at the Oanob Dam near Rehoboth to make
ecological water releases because of the envisaged adverse effect the dam would have on
the downstream riverine vegetation.
3.5
Botswana Water Requirements
3.5.1
Background
In order to assess the water requirements for domestic use at villages and for stock in the
area considered it is important that the accepted boundary line of the Orange River Basin
through southern Botswana is unambiguously defined for planning purposes. Due to the
featureless landscape of the Kalahari Desert in Botswana, it is difficult to define the
boundary along clear topographical features and it will therefore be assumed for the
purpose of the water requirement summary, that the basin boundary follows a straight line
across Botswana from Pitsane near the upper reaches of the Molopo River on the border
between Botswana and South Africa to the border post at Mampunu in Botswana
(Buitepos in Namibia) on the border between Botswana and Namibia. All the villages to the
south of this line and the stock numbers will therefore be included in the assessment of the
domestic and stock water requirements.
29/11/2007
Final
39

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Orange IWRMP
Task 8: Water Requirements
This proposed line differs from the rather arbitrary line shown on the map of the basin in
Figure A-1 of Appendix A is preferred because settlements like, Lehututu , Ncojane and
Mampunu in Botswana, as well as Buitepos and the area to the east of Gobabis in
Namibia is now included. Places along the Trans Kalahari Highway such as Lobatse,
Kanye, the mining town of Jwaneng and Kang in Botswana are still to the north of the
proposed boundary line and therefore not included in the assessment.
The area under consideration is about 120 000km2 in extent or 49 000 square kilometres
more than the area given in the Surface Hydrology Report prepared for this study.
Table 3-13: Catchment data of the Orange River Basin
SURFACE AREA
SURFACE AREA
SHARE OF
SHARE OF
BASIN STATE
OF EACH BASIN
OF ORANGE
STATE IN THE
BASIN IN EACH
STATE
RIVER BASIN
BASIN
STATE
(km²)*
(km²)*
(%)*
(%)*
Botswana
582 000
120 000
12
21
Lesotho
30 000
25 000
3
83
Namibia
824 000
260 000
26
32
South Africa
1 221 000
580 000
59
48
TOTAL
-
985 000
100
-
Note: * - All numbers have been rounded
3.5.2
Water Requirements
The water demand is mainly due to domestic use and stock watering because there are no
mining activities or major irrigation activities in the area under consideration.
The Central Statistics Office (CSO) in Botswana carries out a national population census
every ten years and the last census was done in 2001. There are about 51 villages in the
area and the population in the largest urban centres, Tsabong and Mmathethe, was
respectively only 6 591 and 4 415 while 35 minor settlements had less than 1000 people, 9
rural villages had between 1 000 and 2 000 people, and 3 major villages had between 2
000 and 3 000 inhabitants. The total population in the Orange Basin in Botswana was
about 55 161 in 2001. The total population in Botswana in 2001 was 1 680 863 and
therefore 3,28% of the people in Botswana lived in the Orange Basin. The population
density in the basin area was only 0,46 people per km2 in 2001.
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Task 8: Water Requirements
The 2001 population data for the villages in the area defined above had been used to
make calculations of the estimated population in the years 2005, 2015 and 2025. It is
expected that the increase in the population will generally be affected by increasing
urbanization, better health care, the adverse effects of HIV/AIDS and a decline in
economic activities. From the estimates in the 2001 population census the annual increase
in the population in the Orange Basin will decrease from 1,1 %/annum over the period
2001 to 2010 to 0, 26 %/annum between 2010 and 2020. It was also expected that the
population in the minor villages will reduce between 2001 and 2010 due to migration to the
rural villages, but will increase again at 0, 2% /annum between 2010 and 2020. A
conservative estimate of the future population is shown in Table 3.14.
Table 3-14 : Population data
LOCALITY
POPULATION (Million)
2001
2005
2015
2025
Urban Centres
11 006
11 586
13 174
13 625
Major Villages
7 644
7 898
8 571
8 757
Rural Villages
9 541
12 904
20 300
20 720
Minor Settlements
26 470
24 527
25 034
25 553
TOTAL
54 661
56 915
67 079
68 655
The impact of this scenario on the water demand has not been quantified by the
Government of Botswana and the best information about water demand forecasts is
contained in the 1991 Botswana National Water Master Plan, which is currently under
revision. According to the information, the average water use in the area under
consideration is 75 litres per person per day and this figure will be used to estimate the
future water demand.
It has also been assumed that the grazing capacity in the area is on average about 20
hectares per large stock unit and that stock water consumption is about 30 litres per large
stock unit per day. The Gemsbok National Park in Botswana covers an area of about 12
700 square kilometres and that means that the available rangeland in the basin is about
107 300 square kilometres. The number of stock is therefore in the order of 536 500 and it
is not expected that this number will increase over time, but will most probably fluctuate
around the present number as a result of the availability of grazing due to the seasonal
variations in the rainfall. The estimated stock water demand at 30 per large stock unit per
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day is 5, 875 million cubic metres per annum. Please refer to Table 3.15 for the estimated
water demand in the Orange Basin in Botswana.
It should be noted that no water borne sewage systems are at present in use in most of
the villages and settlements. Such systems have been planned at Tsabong, Goodhope
and Mamunu. Water borne sewage systems and other water intensive projects will cause
a major increase in the water demand.
Table 3-15: Estimated water requirement for Botswana
DEMAND
LOCALITY
(million m3/a)
2005
2015
2025
Domestic use
1.56
1.84
1.88
Livestock
5.88
5.88
5.88
TOTAL
7.43
7.71
7.75
3.6
Lesotho Water Requirements
3.6.1
Population
The 1996 Population Census reported that Lesotho's population in 1996 was 1,968,354,
while the 2001 Lesotho Demographic Survey estimated that the country's population was
2.1 million in 2001. Details of the total population, estimated by the 2001 Lesotho
Demographic Survey (LDS), are shown in the Table 3.16.
Table 3-16 : Distribution of Lesotho's Population by District
District
Total
Butha-Buthe
126,907
Leribe
362,339
Berea
300,557
Maseru
447,599
Mafeteng
238,946
Mohale's Hoek
206,842
Quthing
140,641
Qacha's Nek
80,323
Mokhotlong
89,705
Thaba-Tseka
133,680
TOTAL
2,127,539
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The HIV/AIDS prevalence rate in Lesotho is at a high level because of Lesotho's highly
mobile population and its evolving socio-economic situation. Cultural norms and practices
and the high level of poverty also fuel the epidemic. In addition, the highly mobile
community is largely young men (to South Africa) and young women (to factories in
Lesotho
With HIV/AIDS, the natural growth rate of Lesotho is declining and is projected to continue
to decline until it reaches zero growth rates by 2007/2008, and negative rates thereafter.
This will result in a slow growth of the population until 2010 after which a slow reduction in
population size is projected. The following figure presents the projected population of
Lesotho without AIDS and what this is now likely to be in the face of the high rates of
infection and expected deaths.
Figure 3-2 : Population With and Without AIDS for Lesotho (1986 - 2015)
The Spectrum population projections for both scenarios estimated that the population
would be 2,030,000 and 2,220,000, respectively, for 2001, with the low prevalence
scenario consistent with Bureau of Statistics (BOS) projections.
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Without HIV/AIDS the population was projected to increase to 3.3 million by 2015 but, due
to the impacts of HIV/AIDS, it will only grow to about 2,2 million based on the high HIV
prevalence scenario and 2.32 million based on the low HIV prevalence scenario, meaning
that Lesotho's population will increase only marginally between now and the end of the
decade, and will thereafter decline if no fundamental changes are brought about on a
national scale.
3.6.2
Water Requirements
The supply of water to urban areas in Lesotho relies heavily on direct river extraction and
pumping from underground sources. In recent years, the rapid economic development in
the Lesotho lowlands, with its attendant increase in urban and peri-urban populations and
commercial/industrial activities, has placed an increasing demand on the existing water
supply and sewerage facilities. . It is estimated that by 2005 as much as 78 percent of
Lesotho's 2.3 million people will be living in the Lesotho Lowlands area. Fairly detailed
water demand and demand projection data were obtained from the Lesotho Lowlands
Study report (Lesotho, 2004). These demand projections are summarised in Table 3.17.
For the remainder of Lesotho it was assumed that most of the households represent
unconnected households with a much lower per capita water use. For this purpose 30 l/c/d
was used, which was referred to in the Lesotho Lowland study reports as a recommended
volume for good health. I fact the majority of unconnected households in Lesotho currently
use even less, in the order of 14 to 18 l/c/d.
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Task 8: Water Requirements
Table 3-17 : Summary of urban/Industrial/rural demand projections for Lesotho
Zone & Description
Demand at given development level (million m3/a)
2005
2010
2020
2035
1 Butha Buthe
4.47
6.53
12.17
13.09
2HlotseMaputsoe
5.88
7.74
9.88
12.57
3 Teyateyakeng
2.32
3.04
3.59
3.98
4Maseru zone
26.61
32.00
43.04
59.53
0Maseru only
23.88
29.17
39.99
56.05
5MorijaMatsieng
1.30
1.32
1.38
1.51
6 Mafeteng
4.16
4.49
4.92
5.78
7Mohales Hoek
2.18
6.85
15.90
16.53
8 Quthing
0.93
0.95
1.02
1.15
Subtotal
47.85
62.91
91.90
114.14
Remainder
15.01
15.01
15.01
15.01
Total
62.87
77.93
106.91
129.15
Although Lesotho apparently has abundant water resources, its geographical, seasonal
and annual distribution is uneven and irrigation is therefore still required. Irrigation in
Lesotho is limited and currently only 66ha is irrigated. Previous irrigation projects in
Lesotho have considered 2,637ha, but have failed due to lack of co-operation for many
reasons.
Water for irrigation must be abstracted from one of two sources, from surface water
(rivers) or from groundwater. The greatest potential for substantial quantities of water is
however from the rivers. The quantity of water that can be abstracted from rivers is
determined by the low flows in the river. Keeve Steyn Inc. conducted a "Hydrological
Investigation into Rivers in Lesotho" in 1993. As shown in Table 3.18, they concluded that
those listed were the maximum areas that could be irrigated at the period of minimum flow
with a 15% chance of insufficient water being available (which would lead to crop failure).
This is land which could be sustained for irrigation, with a 15%, ie. a 1 in 7 year, chance of
crop failure, without regulation of the water source.
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Table 3-18 : Maximum Areas Suitable for Irrigation (with a 15% failure chance)
Area
River
Water Requirement (million m3/a)
(hectares)
Hololo
30
0.15
Hlotse
500
5.00
Phuthiatsana North
600
6.00
Phuthiatsana South
350
1.75
Mohokare
Not recommended
Mpetsana
40
0.20
Makhaleng
1 000
10.00
Senqu
1 000
11.50
Total
3 520
34.60
3.6.3
Water Transfers from Lesotho
Over and above the local water requirements in Lesotho, large volumes of water are also
transferred to the RSA by means of the Lesotho Highlands Water Project (LHWP).
The Lesotho Highlands Scheme started operating in 1998, and comprises Mohale and
Katse dams, Matsoku diversion weir, a series of tunnels and a hydro power station. Water
is gravitated through tunnels from Katse Dam (In the Lesotho Highlands) and flows into the
Liebenbergsvlei River via Saulspoort Dam (acting only as a weir), down into the Wilge
River and eventually flows into the Vaal Dam.
The transfer volume has been phased in over a number of years and has almost reached
its maximum of 877 million m3/a. This volume is continuously transferred to the Vaal
System, irrespective of the water situation and dam levels in the RSA. The ecological
requirement releases from the two major dams and Matsoku Weir are summarised in
Table 3.19.
Table 3-19 : Ecological water requirements supplied from LHWP
Requirement
Description
(million m3/a)
Matsoku Weir
20.5
Katse Dam
65.86
Mohale Dam
30.44
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3.7
Assurance of Supply
3.7.1
General
In arid and semi arid regions it is generally not economical feasible to develop and operate
a water resource system to meet all the demands at all times This means that 100% of
the demand can not be supplied for 100% of the time and shortfalls in the supply will occur
from time to time. If shortfalls occur frequently, the supply will have a low assurance while
relative few shortfalls represent a high assurance in supply. Restrictions in supply during
dry periods is therefore one of the few management tools available for operators to cope
with the highly variable stream flow conditions.
It is fairly obvious that different types of user groups or categories will require a different
assurance of supply. Irrigation will typically be supplied at a lower assurance than water
for domestic and industrial purposes and water for strategic industries such as power
generation even at a higher assurance. It is also logic to sub-divide the supply to irrigation
into different assurance levels, as permanent crops such as export grapes would require a
higher assurance than for example a cash crop.
Using only the available historic flow record of 50 to 70 years it is not possible to provide
yield results representing the yield available at high assurances such as a 99% or 99.5%
assurance, which means a possible failure of 1 in 100years and 1 in 200 years
respectively. By using stochastic yield analysis it is possible to determine the system yield
at different reliabilities or assurance levels. At low reliability levels the system can typically
provide a higher yield than would be available at a high reliability level. The stochastic
yield characteristics therefore make it possible to supply the system demands at the
required level of assurance in planning and operational analyses as well as in practise.
For the purpose of these analyses it is therefore important to sub-divide the demand of the
different user categories into three or four priority classes, which represent different
assurance or reliability levels.
3.7.2
Vaal River System
The Integrated Vaal River System is a large and highly complicated system which included
several transfer and support schemes. To be able to properly manage and to do planning
for this system, annual operating analyses are carried out for the integrated system by
using the Water Resource Planning Model (WRPM). The users within the Main Vaal River
System are already supplied according to the assurances defined in the WRPM. The
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combination of assurances of supply as applicable to the different user groups or
categories is referred to as the priority classification set for a particular system. The priority
classification as applicable to the Integrated Vaal River is given in Table 3.20.
Table 3-20 :User Categories and Priority Classifications used for the Vaal System
Priority Classification & Assurance of Supply
Low
Medium
High
User Category
95%
99%
99.5%
1 in 20 year
1 in 100 year
1 in 200 year
Urban/industrial
22%
24%
54%
Industrial (Strategic)
0%
30%
70%
Irrigation
50%
30%
20%
Power Stations
0%
0%
100%
The supply to the user categories were each split into different levels of assurance of
supply. In the Vaal System the user categories were split into three levels of assurance of
supply, namely the low level (95% assurance of supply), medium level (99% assurance of
supply), and the high level (99,5% assurance of supply). In this way a portion of the
demand for a specific user category (say urban) can be supplied at a high level of
assurance (e.g. domestic consumption), while the remaining portion of the demand can be
supplied at a lower level of assurance (e.g. garden watering).
The assurance of supply as applied to the Main Vaal System is however, not imposed on
the smaller sub-systems in the Vaal River catchment. The RSA DWAF is currently in the
process to develop similar operating rules also for the smaller sub-systems, which include
the ability of supplying the users at reasonable and agreed assurance levels. In general it
is expected that the demands in the smaller sub-systems are supplied at lower assurances
than those indicated in Table 3.20 for the Main Vaal System in particular for the diffuse
irrigation.
3.7.3
Orange River System
User categories that were considered for the Orange River Development Project
Replanning Study (ORRS) were urban, industrial, strategic industries, mining, irrigation
and environmental. The urban and industrial users were grouped together due to the fact
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Task 8: Water Requirements
that it was difficult to split the total water demand of a municipality into these two user
categories.
The user categories were each split into different levels of assurance of supply. In annual
operating analysis for the Orange River Main System each of these user categories is sub-
divided into three levels of assurance of supply, namely the low level (95% assurance of
supply), medium level (99% assurance of supply), and the high level (99,5% assurance of
supply). In this way a portion of the demand for a specific user category (say urban) can
be supplied at a high level of assurance (e.g. domestic consumption), while the remaining
portion of the demand can be supplied at a lower level of assurance (e.g. garden
watering).
Table 3-21: User Categories and Priority Classifications used for the Main Orange
System
Priority Classification & Assurance of Supply
Low
Medium
High
User Category
95%
99%
99.5%
1 in 20 year
1 in 100 year
1 in 200 year
Urban/industrial
20%
30%
50%
Losses & river
0%
0%
100%
evaporation
Irrigation
50%
40%
10%
Ecological
33%
0%
67%
Requirements
The reason why river evaporation and conveyance losses are in the high assurance class
is because these losses cannot be curtailed and will still exist during dry periods. The most
realistic option is therefore to include them in the highest assurance class.
The assurance of supply from the transfers from the Lesotho Highlands transfer Scheme
to the Upper Vaal is somewhat lower than 98% assurance. The method of calculating the
assurance as used by the RSA and Lesotho differs slightly. Based on the Lesotho method
the transfer is supplied at a 98% assurance, while the RSA method shows an assurance
somewhat lower than the 98%.
The priority classification for the Caledon/Modder sub-system is given in Table 3.22.
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Task 8: Water Requirements
Table 3-22: User Categories and Priority Classifications used for the Caldon/Modder
Sub-system
Priority Classification & Assurance of Supply
Low
Medium
High
User Category
95%
99%
99.5%
1 in 20 year
1 in 100 year
1 in 200 year
Urban/industrial
20
30
50
Irrigation
50
40
10
The assurance of supply as applied to the Main Orange System is also not imposed on the
smaller sub-systems in the Orange River catchment. In general it is expected that the
demands in the smaller sub-systems are supplied at lower assurances than those
indicated in Table 3.22 for the Main Orange System and in particular for the diffuse
irrigation. Most of the Orange River catchment lays in a much lower rainfall zone than
applicable the Vaal River catchment, so that it is expected that the assurance of supply
particularly in the Lower Orange smaller sub-systems will be much lower.
3.8
Efficiency of Water Use
3.8.1
Irrigation
The two main components in the overal irrigation efficiency are the conveyance losses
and the irrigation system losses. Most literature indicates that an 80% conveyance
efficiency (that is 20% loss through conveyance) is justifiable, considering associated
capital and maintenance costs required. Conveyance losses as currently experienced in
five of the larger irrigation schemes in the Vaal River catchment is summarised in Table
3.23 as obtained from the report `'Potential Savings through WC/WDM in the Upper and
Middle Vaal Water Management Areas''.
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Task 8: Water Requirements
Table 3-23 : Summary of conveyance losses and possible savings
Water Saving
Current Loss
Targeted Loss
Scheme
Difference
Potential
(%)
(%)
(million m3/a)
Schoonspruit
28.5
20
8.5
2.57
Mooi River
24.7
20
4.7
6.1
Allemanskraal
Erfenis
24
20
4
1.87
Vaalharts
32
25
7
29.96
Total
40.5
From Table 3.23 it is clear that substantial savings is possible when conveyance losses
are limited to acceptable values.
Irrigation system losses can be reduced by improved management and scheduling
practises but is to a large extent limited by the type of irrigation system used. Table 3.24
summarises the distribution of different irrigation systems as found in the main irrigation
schemes within the Vaal River catchment.
Table 3-24 : Percentage of Irrigation systems in the selected five schemes
Type of Irrigation
Irrigation
% of Irrigation systems in Irrigation schemes
System
Efficiency Schoonspruit Erfenis Allemanskraal Vaalharts* Klerksdorp Mooi
Flood
65.0%
60.0%
3.0%
8.0%
70.0%
25.0%
60.0%
Mechanical
80.0%
15.0%
93.0% 73.0%
10.0%
0.0%
15.0%
Sprinkler
75.0%
25.0%
4.0%
18.0%
15.0%
75.0%
25.0%
Micro
85.0%
0.0%
0.0%
1.0%
3.0%
0.0%
0.0%
Drip
90.0%
0.0%
0.0%
0.0%
2.0%
0.0%
0.0%
Scheme Efficiency
0.70
0.79
0.78
0.69
0.73
0.70
Flood irrigation is still widely used in most of the schemes. With an overall improvement of
only 5% in the irrigation efficiency, it will be possible to save approximately 18 million m3/a.
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Task 8: Water Requirements
As part of the Lower Orange River Management Study (LORMS) a report was produced
on WC/WDM. This is the most recent work produced on WC/WDM for the Greater Orange
River System. Irrigation is the largest water consumer in the Orange and fairly substantial
savings can be achieved by means of WC/WDM. Results from the LORMS study is
summarised in Table 3.25.
Table 3-25: Possible savings through WC/WDM in the irrigation sector
Existing
Possible water savings (Million m3/a)
Requirement
Percentage
River Reach
Irr
(Million
Metering
Saving
Scheduling
System
Total
m3/a)
& Pricing
Efficiency
Caledon and
Orange upstream of
102
7.2
6.7
8.4
22.3
21.9%
Gariep Dam
Riet/Modder &
Orange River to
1 269
63.9
84.3
115.5
263.7
20.8%
Namibia Border
Orange River on
Common Border
102
3.6
6.9
6.2
16.7
16.9%
between Namibia &
RSA
Total
1 473
74.7
97.9
130.1
302.7
20.5%
Only estimated conveyance losses in the canal distribution systems in the Orange and
Riet/Modder catchments were available from the LORMS reports. These are summarised
in Table 3.26.
Table 3-26 : Estimated Canal Losses in the Orange and Modder/Riet systems
Description
Estimated canal
Estimated
Net Canal
Net loss as % of
losses (million
Return flow
loss (million
gross inflow (million
m3/a)
(million m3/a)
m3/a)
m3/a)
Ramah &
11.03
6.62
4.41
6.0
Vanderkloof canal
Orange Riet canal
22,67
1.13
21.54
14.3
Lower Riet
6.35
0.32
6.03
14.3
Kalkfontein
5.91
3.55
2.36
6.0
Scheme
Douglas Weir
11.75
3.53
8.22
10.5
Boegoeberg
20.01
12.00
8.01
6.0
Canal
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Description
Estimated canal
Estimated
Net Canal
Net loss as % of
losses (million
Return flow
loss (million
gross inflow (million
m3/a)
(million m3/a)
m3/a)
m3/a)
Upington Canal
17.45
10.47
6.98
6.0
Keimoes Canal
13.47
8.08
5.39
6.0
Kakamas Canal
10.05
6.03
4.02
4.0
Vioolsdrift South
1.59
0.95
0.64
6.0
Vioolsdrif North
1.01
0.60
0.41
6.0
Aussenkehr
1.45
0.87
0.58
6.0
Total
189.07
54.15
68.59
No detailed investigation was done to determine the seepage, evaporation losses and
leakage on the canals. The estimated values are however not sufficient to determine the
possible efficiency improvements through canal rehabilitation, as detailed investigations
are required combined with observed data.
3.8.2
Urban/Industrial
From the assessment of the scope for WC/WDM that was carried out as part of the "Vaal
River System: Large Bulk Water Supply Reconciliation Strategies" study the following
2004/05 demands and related total system losses were obtained as given in Table 3.27.
The losses refer to all the losses (real and apparent) that occurs in the distribution system
up to the consumers metering point. Losses within the internal supply system of the
consumers are therefore excluded. From these results it seems that on average
approximately 25% losses are experienced within the Rand Water supply area.
It should however be noted that the use of percentages can be very misleading due to the
fact that percentage figures are strongly influenced by the consumption. Typically one
would see that the percentage losses tend to be higher for the smaller users, although the
potential for savings might not be very high for these small users.
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Table 3-27 : Losses within the Rand Water supply area
Annual
Area
Demand
Total loss
Percentage
(million
(million
cub.m/a)
cub.m/a)
loss
Johannesburg 470
90.87
19.3
Ekurhuleni
291
69.02
23.7
Tshwane
255
62.67
24.6
Emfuleni
79
36.2
45.8
Rustenburg
26
8.17
31.4
Mogale
24
6.12
25.5
Govan Mbeki
18
9.05
50.3
Matjhabeng
16
9.05
56.6
Randfontein
7
1.9
27.1
Total
1186
293.05
24.7
The WC/WDM report from the "Vaal River System: Large Bulk Water Supply
Reconciliation Strategies" study concluded that the projected Rand Water demand can
over time be reduced by between 13% to 27% through the implementation of WC/WDM
measures..
Urban/industrial demands in the Orange River System are a very small component of the
total demand. The impact of WC/WDM within this sector will therefore have a very small
impact on the overall water use. The LORMS however did indicate that the biggest
potential to improve the efficiency of water use, are within the mining related towns of
Alexanderbay, Oranjemund and Rosh Pinah. The residents in these towns receive
unmetered water, free of charge, which leads to wastage.
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4
CONCLUSIONS AND RECOMMENDATIONS
4.1
Conclusions
4.1.1
Vaal River Systems
The water resources of the Vaal River system are an important asset to the RSA and its
people supporting major economic activities and a population of almost 12 million people.
Demands imposed on the main Vaal System are in general well defined and updated on a
regular basis, as part of the annual operating analysis carried out for the integrated Vaal
River System. This system is largely utilised to supply water to urban/industrial/mining and
power stations (65%), with irrigation (19%) being a much smaller component. Only surface
water resources are used to supply these demands.
The resources within the Vaal Basin itself is not sufficient to supply in the large demand of
almost 2 800 million m3/a currently imposed on the system. Several major transfer
schemes were therefore introduced to augment the ever increasing demand in the basin.
Indications are that intervention will again be required by approximately 2013. The
intervention will most probably include a combination of water conservation and demand
management actions, together with a transfer scheme.
The ecological requirements for both the main Vaal System as well as for the smaller
systems are based on desktop estimates recently determined by the RSA DWAF. These
environmental requirements are only first order indications of what the ecological reserve
will be, and are thus currently not supplied by means of any releases from the reservoirs.
The demands imposed on the smaller systems within the Vaal River Basin is not supplied
or supported from the main Vaal system. It however impacts significantly on the main Vaal
System, as large volumes of water is utilised in these smaller systems, which reduces the
total volume of water reaching the main system. The total water use from the smaller
systems accumulates to 1 055 million m3/a at 2005 development level. The bulk of the
water use in the smal er systems is for irrigation purposes, representing 64% of the total
demand.
Most of the demands are supplied from surface water resources with the
exception of the rural domestic and livestock requirements, which are mainly met from
groundwater resources.
Data for demands imposed on the smaller systems and in particular for the diffuse
irrigation demands are at a lower confidence level than those available for the main Vaal
System. Indications from the verification and validation of registered water use in the Vaal
29/11/2007
Final
55

---

Orange IWRMP
Task 8: Water Requirements
Basin showed that the diffuse irrigation is significantly more than previously estimated. A
large amount of the irrigation use (241 million m3/a) is expected to be unlawful and need to
be eradicated
The confidence level on groundwater use related data is in general much lower than that
from surface water. There is not always a clear cut sub-division between whether surface
or groundwater resources are used to supply the certain demands, in particular with
regards to diffuse irrigation requirements. Reliable data in this regard should become
available at the completion of the validation and verification of the registered water use in
the RSA.
The bulk of the return flows in the Vaal River basin are generated from the urban/industrial
sector in the Gauteng area. Approximately 50% of the total demand is received as return
flows from this area, producing in excess of 600 million m3/a, of which 335 million m3/a
returns to the Vaal River while the remainder (270 million m3/a) end up in the Crocodile
West River catchment. Increased urban runoff due to paved areas and mine dewatering
each add another 114 million m3/a, and 101 million m3/a respectively. Return flows from
the main irrigation schemes accumulates to almost 70 million m3/a, or approximately 12%
of the gross irrigation demand. Although the large volumes of return flows from the Vaal
catchment improves the water availability in the catchment, it has a negative effect on the
quality of the water, to such an extent that operational measures had to be introduced to
improve the quality in certain river reaches.
4.1.2
Orange River Systems
In contradiction to the main Vaal System, the main Orange System or ORP is used to
mainly supply water for irrigation purposes (approximately 60% of demand), with a small
portion (only 2.5%) of the demand comprising of urban/industrial & mining requirements.
Irrigation demands are in general obtained by the quota for the given area times the
allocated irrigation area. There is very little observed measured irrigation abstraction data
available and the actual true irrigation use will differ from that obtained from the allocated
area and quota. Although this data is, as in the case for the Vaal System, also updated on
an annual basis as part of the operational analysis, it is not to the same confidence level
as that of the Vaal, due to the large irrigation component.
Return flows from
urban/industrial requirements is almost negligible and those from irrigation amounts to 207
million m3/a, or 13% of the gross irrigation requirement.
29/11/2007
Final
56

---

Orange IWRMP
Task 8: Water Requirements
The main Orange River System in not supported or augmented by any other sub-system.
Water is in fact transferred from the Orange River Main System to support other sub-
systems such as the Eastern Cape, the Riet/Modder, Douglas in the Lower Vaal etc. With
the current expected growth in demand, the main Orange River System will require
intervention by 2012. This is expected to be accomplished by increased system efficiency
in combination with utilising Vanderkloof Dam lower level storage and or a dam at
Vioolsdrift.
The river mouth ecological requirement currently released from Vanderkloof Dam amounts
to 289 million m3/a, and is based on fairly old methodology. Recent estimation of the
ecological requirement indicated an average requirement of in the order of 1 062 million
m3/a. This ecological requirement has not been implemented as it was not determined at a
detailed level and only provided and better indication of what the reserve could be.
Ecological requirements as determined and implemented for the LHWP were recently
updated and can be used with confidence.
The total demand, transfers included from the other systems in the Orange Basin is in
excess of 1 400 million m3/a, which wil have a significant impact on the water availability in
the main Orange System. Most of the demands are supplied from surface water resources
with the exception of the rural domestic and livestock requirements which are mainly
supplied from groundwater. The demands and transfer data with regards to the LHWP
and the Caledon/Modder transfer are at a fairly high confidence level. The confidence
level with regards to groundwater use is in general much lower than those from surface
water resources. The smaller towns as well as diffuse irrigation are in many cases
supplied by both surface and groundwater resources, making it difficult to allocate the
demand to the correct resource.
4.2
Recommendations
· The confidence in groundwater related data need to be improved in both the
Orange and Vaal River Systems. This must include the distinction between
groundwater and surface water use in particular when both the resources are
used to supply a specific demand centre.
· Ecological requirements given for the Vaal Systems and the Main Orange System
should be treated with caution as they are only preliminary values, used to
provide an indication of what the reserve could be. These values should be
replaced when more recent and up to date estimations are available.
29/11/2007
Final
57

---

Orange IWRMP
Task 8: Water Requirements
· Unlawful irrigation need to be eradicated and controlled as it has a significant
effect on the total water demand imposed on the systems.
· High return flow volumes are available from both the Vaal and Orange River
systems. One should be very careful in allocating those return flows for other
uses as more efficient use in the systems can lead to significant reductions in
return flows.
· Results from Verification / Validation studies should be used to improve the
confidence level of data currently used in models, as soon as it becomes
available.
· The irrigation demand is in the Orange systems the largest and in the Vaal
systems the second largest water consumer. Very little of the irrigation use is
however metered. It is recommended that measures should be put in place to
encourage the proper metering and recording of irrigation abstractions.
· There is a need to do a proper survey within the Orange River basin in Botswana
to determine the location of new settlements, villages and towns, the number of
people, the number of livestock the different water uses and the quantity of water
used in order to make present and future water demand assessments based on
more accurate information.
· There is a need to update the 2000 assessment of the present and future water
demand in Namibia with specific reference to the Orange River Basin.
29/11/2007
Final
58

---

Orange IWRMP
Task 8: Water Requirements
5
REFERENCES
AtlasSWA (1983)
National Atlas of South West Africa. By JH van
der Merwe, 1983
Botswana WSDM(1989)
Rural Village Water Supply Design Manual. By
the Department of Water Affairs Botswana, 1989.
Botswana NWMP(1991)
Botswana National Water Master Plan. Report
prepared by SMEC, WLPU Consultants and
Swedich Geological International. 1991.
DWAF (1993)
Orange
River
System
Analysis.
Caledon,
Modder and Riet Rivers: Yield Analysis. Report
no P D 000/00/1092, P D 200/00/0192, P C
500/00/0792 by BKS Incorporated Consulting
Engineers
and
Stewart
Sviridov
&
Oliver
Consulting Engineers for the Department of Water
Affairs and Forestry, Pretoria, South Africa, March
1993. Prepared by Project Team.
Census (1994)
1991 Population and Housing Census Namibia.
By Census Office, National Planning Commission,
1994
DWAF (1997)
Orange River Development Project Replanning
Study.
Hydrology
and
System
Analysis
-
Orange River Basin. Report no PD 000/00/4697
by BKS (Pty) Ltd and Ninham Shand (Pty) Ltd for
the Department of Water Affairs and Forestry,
Pretoria South Africa, May 1997. Prepared by R S
McKenzie and H G Maré.
29/11/2007
Final
59

---

Orange IWRMP
Task 8: Water Requirements
DWAF(2000a)
Vaal River System Analysis Update. Historic
and Long-Term Stochastic Yield Analysis of
the Grootdraai Dam and Bloemhof Dam sub-
systems. Report no PC 000/00/17696 by BKS
(Pty) Ltd, Stewart Scott Inc and Ninham Shand
(Pty) Ltd for the Department of Water Affairs and
Forestry, Pretoria South Africa, February 2000.
Prepared by H G Maré.
DWAF(2000b)
Vaal River System Analysis Update. Historical
and Long- Term Stochastic Yield Analysis of
the
Senqu
sub-system.
Report
no
PC
000/00/17796 by BKS (Pty) Ltd, Stewart Scott Inc
and Ninham Shand for the Department of Water
Affairs and Forestry, Pretoria, South Africa,
February 2000. Prepared by P G Van Rooyen, H
G Maré and O Viljoen.
WCE (2000)
Analysis of Present and Future Water Demand
in Namibia. By Windhoek Consulting Engineers,
2000.
Census (2002)
2001 Population and Housing Census. By
Census Office, National Planning Commission,
2002.
DWAF (2002a)
Upper Vaal Water Management Area: Water
Resources
Situation
Assessment
­
Main
Report
­
Volume
1
of
3:
Report no.
P08000/00/0101 by Stewart Scott Consulting
Engineers for the Department of Water Affairs and
Forestry, Pretoria, South Africa, July 2002.
Prepared by Project Team.
29/11/2007
Final
60

---

Orange IWRMP
Task 8: Water Requirements
DWAF (2002b)
Middle Vaal Water Management Area: Water
Resources
Situation
Assessment
­
Main
Report
­
Volume
1
of
3:
Report no.
P09000/00/0101 by Stewart Scott Consulting
Engineers for the Department of Water Affairs and
Forestry, Pretoria, South Africa, August 2002.
Prepared by Project Team.
DWAF (2002c)
Lower Vaal Water Management Area: Water
Resources
Situation
Assessment
­
Main
Report :
Report no. P10000/00/0301 by BKS
(Pty)Ltd for the Department of Water Affairs and
Forestry, Pretoria, South Africa, August 2002.
Compiled by C Delport & SJL Mallory.
DWAF (2002e)
Upper Orange Water Management Area: Water
Resources
Situation
Assessment
­
Main
Report-
Volume
1
of
3
:
Report no.
P13000/00/0101 by Stewart Scott Consulting
Engineers for the Department of Water Affairs and
Forestry, Pretoria, South Africa, August 2002.
Compiled by WV Pitman, AK Bailey, AB Beater.
DWAF (2002f)
Lower Orange Water Management Area: Water
Resources
Situation
Assessment
­
Main
Report-
Volume
1
of
2
:
Report no.
P14000/00/0101 by V3 Consulting Engineers for
the Department of Water Affairs and Forestry,
Pretoria, South Africa, March 2002. Compiled by
AJ Smook, DJ Pournara, AR Craig.
29/11/2007
Final
61

---

Orange IWRMP
Task 8: Water Requirements
DWAF (2002g)
Orange River Continuous Studies Task 15.
Caledon - Modder River System Planning
Analysis: Effect of Updated Water Requirement
Projections
based
on
the
National
Water
Resources Strategy Study. Report no P876615
by
BKS
Engineering
Management
for
the
Department of Water Affairs and Forestry, Pretoria,
South Africa, February 2002. Prepared by H G
Maré and R Dube.
Botswana Population(2002)
Population and Housing Census. By Central
Statistics Office, Botswana Government. 2002
DWAF (2004a)
Internal Strategic Perspective for the Vaal River
System Overarching (WMAs No. 8, 9 & 10).
Report no. P RSA C000/00/0103 by PDNA, WRP
Consulting Engineers (Pty) Ltd, WMB and Kwezi-
V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, March 2004.
DWAF (2004b)
Internal Strategic Perspective for the Upper
Vaal Water Management Area (WMA No. 8).
Report no. P WMA 08/000/00/0304 by PDNA,
WRP Consulting Engineers (Pty) Ltd, WMB and
Kwezi-V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, March 2004.
DWAF (2004c)
Internal Strategic Perspective for the Middle
Vaal Water Management Area (WMA No. 9).
Report no. P WMA 09/000/00/0304 by PDNA,
WRP Consulting Engineers (Pty) Ltd, WMB and
Kwezi-V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, July 2004.
29/11/2007
Final
62

---

Orange IWRMP
Task 8: Water Requirements
DWAF (2004d)
Internal Strategic Perspective for the Lower
Vaal Water Management Area (WMA No. 10).
Report no. P WMA 10/000/00/0304 by PDNA,
WRP Consulting Engineers (Pty) Ltd, WMB and
Kwezi-V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, October 2004.
DWAF (2004e)
Internal Strategic Perspective for the Upper
Orange Water Management Area (WMA No. 13).
Report no. P WMA 13/000/00/0304 by PDNA,
WRP Consulting Engineers (Pty) Ltd, WMB and
Kwezi-V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, April 2004.
DWAF (2004f)
Internal Strategic Perspective for the Lower
Orange Water Management Area (WMA No. 14).
Report no. P WMA 14/000/00/0304 by PDNA,
WRP Consulting Engineers (Pty) Ltd, WMB and
Kwezi-V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, July 2004.
DWAF (2004g)
Internal Strategic Perspective for the Orange
River System Overarching (WMAs No. 13 &14).
Report no. P RSA D000/00/0104 by PDNA, WRP
Consulting Engineers (Pty) Ltd, WMB and Kwezi-
V3 for the Department of Water Affairs and
Forestry, Pretoria, South Africa, July 2004.
LESOTHO (2004)
Lesotho
Lowlands
Water
Supply
Scheme:
Consultancy Services for a Feasibility Study of
the Scheme. Main Report Volume1 & 2. Report
by Parkman for the Kingdom of Lesotho &
European Commission 8th EDF National Indicative
Programme. June 2004.
29/11/2007
Final
63

---

Orange IWRMP
Task 8: Water Requirements
PWC ( 2004h)
Hydrology, Water Quality and System Analysis
Volume A (Draft 2). Pre-Feasibility Study into
Measures to improve the Management of the
Lower Orange River and to provide for future
developments
along
the
Border
between
Namibia and South Africa. Report no PB D
000/00/4303 by Burmeister & Partners, Ninham
Shand (Pty) Ltd, Windhoek Consulting Engineers
and WRP (Pty) Ltd for the Permanent Water
Commission, The Republic of Namibia, The
Republic of South Africa, October 2004. Prepared
by H G Maré, L C Hattingh, W Kamish and Project
Team.
DWAF(2006a)
Vaal River System: Large Bulk Water Supply
Reconciliation
Strategy:
First
stage
reconciliation
study.
Report
no
P
RSA
C000/00/4405/07
by
DMM
Development
Consultants, Golder Associates Africa, SRK, WRP
Consulting Engineers and Zitholele Consulting for
the Department of Water Affairs and Forestry,
Pretoria, South Africa, December 2006. Prepared
by PG van Rooyen and study Team.
DWAF(2006b)
Vaal River System: Large Bulk Water Supply
Reconciliation Strategy: Irrigation water use
and
return
flows.
Report
no
P
RSA
C000/00/4405/04
by
DMM
Development
Consultants, Golder Associates Africa, SRK, WRP
Consulting Engineers and Zitholele Consulting for
the Department of Water Affairs and Forestry,
Pretoria, South Africa, December 2006. Prepared
by HG Maré.
29/11/2007
Final
64

---

Orange IWRMP
Task 8: Water Requirements
DWAF(2006c)
Vaal River System: Large Bulk Water Supply
Reconciliation
Strategy:
Water
Resource
Analysis. Report no P RSA C000/00/4405/05 by
DMM
Development
Consultants,
Golder
Associates
Africa,
SRK,
WRP
Consulting
Engineers and Zitholele Consulting for the
Department of Water Affairs and Forestry, Pretoria,
South Africa, December 2006. Prepared by HS
Swart.
DWAF(2007)
Vaal River System: Annual Operating Analysis
2006/2007. Report no P RSA C000/00/4405/05 by
WRP Consulting Engineers for the Department of
Water Affairs and Forestry, Pretoria, South Africa,
July 2007. Prepared by HS Swart.
29/11/2007
Final
65

---

Orange IWRMP
Task 8: Water Requirements
Appendix A
Figures
Figure no
1) Orange River Catchment Base Map
A-1
2) Minor sub-catchments and related reference numbers
A-2
3) Transfers to and from the Integrated Vaal River Water Supply
System
A-3
4) Transfers from the Larger Orange River Supply System
A- 4
5) Schematic of the integrated Vaal River System
A-5
6) Schematic of the Larger Orange River System
A-6
7) Demand distribution in the Orange River Basin
A-7
8) Groundwater use in the Orange River Basin
A-8
29/11/2007
Final
66

---

Black Nossob
Buitepos
Otjivero
White
# #
N
Mamuno
o
Daan Viljoen
sso
S
#
e
Gobabis
eis
b
WINDHOEK %
BOTSWANA
Nauaspoort
# Ncojane
# Rehoboth
Oanob
O
S
a
k
n
a
o
ap
# Kang
b
Olif
#
an
Lehututu
st
Lower Orange
Fish
Botswana
Au
Hardap
ob
Jwaneng #
GABARONE %
# Mariental
Nossob
Le
# Kanye
w
Lower Orange
er
Namibia
Lobatse #
Molopo
sab
Goodhope # #
A
Pitsane
NAMIBIA
GAUTENG
PRETORIA
Auob
%
Kanibes
MAFIKENG
Vygeboom
#
#
Helmeringhausen
JOHANNESBURG
K
Tshabong
o
Nooitgedag
mati
Fish
Namibia
Vaal Barrage
K
Westoe
onk
# Keetmanshoop
% VEREENIGING
i
Vaal Barrage
Jericho
ep Seeheim
SWAZILAND
#
Vaal
Vaal
#
Vanzylsrus
Loewen
Ku
#
Grootdraai
ruman
#
Morgenstond
#
Naute
Wentzel
Vaal
Fish
REPUBLIC OF SOUTHG AFRICA
Schweizer-Reneke
Orkney
Parys
Standerton
#
Renoster
B
a
Sandsp
Heyshope
a
Molopo
k
m
ruit
m
# Kuruman
a
Harts
Vals
g
Upper Vaal
a
Taung
Bloemhof
W
ra
Middle Vaal
i
Zaaihoek
Lower Vaal
lg
G
V
a
e
e
ia
t
B
b
u
Ais Ais
Spitskop
f
S
% WELKOM
e
Rosh Pinah
#
Liebenbergsvlei
l
#
Gamkab
# Karasburg
Lower Orange
a nd
s
Tsamab
Dreihuk
RSA
Vaalharts Weir
Allemanskraal
Saulspoort
Harrismith
H
H
a
V
o
m
e
#
Aussenkehr
Riemvasmaak
t
#
m
#
#
Upington
Erfenis
Sterkfontein
Haib
Augrabies
Oranjemund
#
#
#
Spioenkop
#
Keimoes
Vaal
%
#
Tuge
Onseepkans
#
O
KIMBERLEY
Krugersdrif
la
T
Alexander Bay
#
Orange
Kakamas
ra
u
n
M
Modder
a
Woodstock
ge
Vioolsdrift
# Goodhouse
H
ge
Douglas #
# Ritchie
Mockes
l
la
a
bi
r
Boegoeberg
Douglas Weir
tb
%
Caledon
a
ee
Riet-Modder
Katse
BLOEMFONTEIN
m
s
Riet
MASERU
a
Tierpoort
Rusfontein
t
%
s
Rooiberg
Kalkfontein
o
S
Mohale
en
#
#
Prieska
Hopetown
CaledonLESOTHO quny Senqu
Welbedacht
a
Verneuk Pan
ne
Grootvloer Pan
B
Van der Kloof
rak
Ora
Senqu
Vanwyksvlei
nge
Smartt Syndicate
Gariep
# Aliwal North
On
Seekoei
Upper Orange
g
Kraai
S
e
a
r
k
s
Brak
Vis R
Sak
Botswana catchment boundary
eno R
s
i
Initial Botswana and Namibia catchment boundary
t
et
Namibia catchment boundary
100
0
100
200
300
400
500 km
WRP_P0123_ORANGE SENQU_A-1.apr
INTEGRATED WATER RESOURCES MANAGEMENT PLAN
Orange River Catchment Base Map and Main Sub-catchments
FOR THE ORANGE-SENQU RIVER BASIN
A-1

---

Black Nossob
N1
Otjivero
White
Sub-catchment Reference Number
N
N2
o
Daan Viljoen
ss
$$
o
S
#
e
Gobabis
R Country indicator
eis
b
WINDHOEK %
R22 22 Sub-catchment number
N4
Nauaspoort
B Botswana
N5 # RehobothS
BOTSWANA
R Republic of South Africa
Oanob
O
N3
a
k
n
a
o
a
b
p
L Lesotho
Olifan
N Namibia
st
FiF
N12
sh
Au
Hardap
ob
GABARONE %
# Mariental
Nossob
Lewer
N6
Lobatse #
Molopo
sab
N16
A
NAMIBIA
B1
PRETORIA
Auob
%
Kanibes
Tshabong
MAFIKENG
Vygeboom
#
#
Helmeringhausen
JOHANNESBURG
Ko
R13
Nooitgedag
mati
R18
R23
R20
R11
R7
K
R8
R15
Westoe
on
R22
kn
# Keetmanshoop
% VEREENIGING
ie
Vaal Barrage
Jericho
p Seeheim
#
R6
Vaal
Vaal
#
Vanzylsrus
Loewen
R17
N15
K
#
Grootdraai
uruman
N13
#
Morgenstond
R3
R5
#
Naute
Schweizer-Reneke
Orkney
Parys
Wentzel
Vaal
Standerton
Fish
Naute
G
#
Renoster
B
a
Sand
R10
sp
Heyshope
a
Molopo
k
m
ruit
R25
R24
m
N14
#
R19
RSA
Kuruman
a
Harts
Vals
g
R16
a
Taung
Bloemhof
W
R1
r
Zaaihoek
a
ilg
G
V
a
e
e
ia
R27
t
B
b
R14
u
Ais Ais
N8
N7
R45
Spitskop
WELKOM
f
Karasburg
S %
R2
e
Rosh Pinah
#
Liebenbergsvlei
l
#
Gamkab
#
and
s
R26
Vaalharts Weir
N11
N10
Tsamab
Dreihuk
R21
Allemanskraal
Saulspoort
Harrismith
Aussenkehr
H
H
a
N9
V
m
e
#
Riemvasmaak
o
t
#
m
#
#
Upington
R28
R9
R29
Erfenis
Sterkfontein
Haib
Augrabies
Oranjemund
#
R4
#
#
R42
L12
Spioenkop
#
Keimoes
Vaal
%
#
Tuge
Onseepkans
#
O
KIMBERLEY
Krugersdrif
la
R12
T
Alexander Bay
#
Orange
Kakamas
ra
u
n
M
Modder
R32
a
Woodstock
ge
Vioolsdrift
# Goodhouse
H
ge
Douglas #
# Ritchie
R35
Mockes
L11
il
la
a
L1 b
r
Boegoeberg
Douglas Weir
t
L4
b
%
R43
a
ee
BLOEMFONTEIN
Katse m
s
Riet
MASERU
a
R30
Tierpoort
Rusfontein
t
%
s
Rooiberg
Kalkfontein
L5
o
L3
R34 R33
Mohale
Sen
#
#
Prieska
Hopetown
q
Caledon
u
R31
R41
ny L2
Welbedacht
a
Verneuk Pan
R44
LESOTHO ne
L7
Grootvloer Pan
B
Van der Kloof
L6
ra
L8
k
Ora
Senqu
Vanwyksvlei
nge
Smartt Syndicate
R36
Gariep
# Aliwal North
On
Seekoei R38
g
R37 + R40
Kraai
S
e
a
r
k
s
R39
Brak
Vis R
Sak
eno R
s
i
t
et
100
0
100
200
300
400
500 km
WRP_P0123_ORANGE SENQU_A-2.apr
INTEGRATED WATER RESOURCES MANAGEMENT PLAN
FOR THE ORANGE-SENQU RIVER BASIN
Minor Sub-catchments and Reference Numbers
A-2

---

---

---

---

---

Black Nossob
Otjivero
White No
Daan Viljoen
sso
S
#
e
Gobabis
eis
b
WINDHOEK %
Total Catchment Demand
BOTSWANA
3%
3%
Nauaspoort
8%
# Rehoboth
Oanob
O
S
a
k
n
a
o
a
b
p
25%
Olifan
47%
st
10%
Fish
Au
4%
Hardap
ob
GABARONE %
7691
# Mariental
Nossob
21%
Lew
Lower Orange
er
Namibia
Lobatse
79%
#
Molo
7
po
sab
A
GAUTENG
NAMIBIA
Lower Orange
1% 7%
Au
Botswana
PRETORIA
ob
%
10%
Kanibes
MAFIKENG
Vygeboom
#
#
Helmeringhausen
JOHANNESBURG
K
Tshabong
o
75%
15%
16%
Nooitgedag
mati
82%
27%
7%
Fish
10% 0.2% (Rural)
677
Namibia
158
Vaal Barrage
K
50%
Westoe
onk
# Keetmanshoop
% VEREENIGING
i
Vaal Barrage
Jericho
ep Seeheim
559
SWAZILAND
#
Vaal
Vaal
#
Vanzylsrus
Loewen
Ku
#
Grootdraai
ruman
#
Morgenstond
#
Naute
Wentzel
Vaal
Fish
REPUBLIC OF SOUTHG AFRICA
Schweizer-Reneke
Orkney
Parys
Standerton
#
Renoster
Upper Vaal
B
a
Sandsp
Heyshope
a
Molopo
k
m
ruit
m
# Kuruman
3%3%
a
Harts
Vals
ga
Taung
Bloemhof
W
ra
4%
Middle Vaal
i
Zaaihoek
Lower Vaal
lg17%
G
V
a
e
e
ia
t
B
b
9%
52%
u
Ais Ais
Spitskop
f
30%
S
% WELKOM
e
Rosh Pinah
#
Liebenbergsvlei1525
l
#
Gamkab
# Karasburg
Lower Orange
a nd
16%
s
Tsamab
Dreihuk
RSA
Vaalharts Weir
Allemanskraal 4%
Saulspoort
H
61%
H
a
5%
V
o
m
e
#
Aussenkehr
Riemvasmaak
Harrismith
t
#
m
#
#
UpingtonO
18%
r
818
Erfenis
Sterkfontein
Haib
Augrabies
an
28%
Oranjemund
#
#
#
ge
Spioenkop
#
Keimoes
Vaal
%
#
Tuge
Onseepkans
#
KIMBERLEY
Krugersdrif
la
50%
T
Alexander Bay
#
Orange
Kakamas
M
Modder
u
2%
86
a
Woodstock
ge
Vioolsdrift
# Goodhouse
H
Boegoeberg
Douglas #
# Ritchie
Mockes
l
la
a
2%
Douglas Weir
bi
rtb
13%
%
a
ee
Riet-Modder
Katse
BLOEMFONTEIN
Caledon
m
s
Riet
a
27%
Tierpoort
Rusfontein
MASERU
t
3%
%
so
Rooiberg
10% 16%
1043
43%
Kalkfontein
S
Mohale
e
13%
473
n
#
#
Prieska
Hopetown
Caledon
2246
LESOTHO quny
11.2% 0.8%
71%
Welbedacht
a
Verneuk Pan
Senqu n
1.0%
e
84.1%
3.0%
Grootvloer Pan
Bra
Van der Kloof
k
Ora
Senqu
Vanwyksvlei
nge
Botswana catchment boundary
2%
Smartt Syndicate
3%
Gariep
# Aliwal North
Initial Botswana and Namibia catchment boundary
On
Seekoei Upper Orange
g
Kraai
Namibia catchment boundary
S
e
a
r
k
s
Demand Distribution
95%
1100
Losses
River Evaporation
Brak
Rural
Transfers
Vis R
Sak
e
Irrigation
Ecological Requirements
no
R
s
i
t
et
Strategic Industries
Urban / Industrial / Mining
Power Stations
Domestic
Total Demand 2005 (million m³/a)
100
0
100
200
300
400
500 km
Livestock
WRP_P0123_ORANGE SENQU_A-7b.apr
INTEGRATED WATER RESOURCES MANAGEMENT PLAN
Surface Water Demand Distribution in Orange River Basin
FOR THE ORANGE-SENQU RIVER BASIN